Collection of tasks for summative assessment ... - nis.edu.kz

Collection of tasks for summative assessment for the term

on the subject "Physics"

(advanced level)

Grades 11-12

GRADE 11

Sample questions and mark scheme

Tasks for the Summative Assessment for the term 1

QUESTIONS WITH MULTIPLE CHOICE ANSWERS

1.Three velocity vectors, u, v and X are shown in the diagram.

Which statement about the vectors is correct?

A. v added to u produces a resultant X

B. u added to X produces a resultant v

C. the magnitude of v equals the sum of the magnitude of u and the magnitude of X

D. the magnitude of u equals the sum of the magnitude of X and the magnitude of v.

[1]

2. The graph of velocity against time for an object moving in a straight line is shown.

Which of the following is the corresponding graph of displacement against time?

[1]

3. A balloon inflated with helium gas (density = 0.2 kg/m3) has a volume of 6 × 10

3 m

3. If the

density of air is 1.3 kg/m3, what is the buoyant force exerted on the balloon.

A. 0.01 N

B. 1.3 N

C. 0.8 N

D. 0.08 N [1]

4. Four different students use a ruler to measure the length of a 15.0 cm pencil. Their measurements

are recorded on four different charts.

Which chart shows measurements that are precise but not accurate?

[1]

5. In a simple electrical circuit, the current in a resistor is measured as (2.50 ± 0.05) mA. The

resistor is marked as having a value of 4.7 Ω ± 2 %. If these values were used to calculate the

power dissipated in the resistor, what would be the percentage uncertainty in the value obtained?

A 2 % B 4 % C 6 % D 8 % [1]

6. Four cuboids with identical length, breadth and height are immersed in water. The cuboids are

held at the same depth and in identical orientations by vertical rods, as shown.

Water has density ρ.

Cuboid W is made of material of density 4ρ.

Cuboid X is made of material of density 2ρ.

Cuboid Y is made of material of density ρ.

Cuboid Z is made of material of density 0.5ρ.

Which statement is correct?

A. The upthrust of the water on each of the cuboids is the same.

B. The upthrust of the water on W is twice the upthrust of the water on X.

C. The upthrust of the water on X is twice the upthrust of the water on W.

D. The upthrust of the water on Y is zero. [1]

7. A large tank is filled with water to a depth

of 15 m. A spout located 10.0 m above the

bottom of the tank is then opened as shown

in the drawing. With what speed will water

emerge from the spout?

A. 3.1 m/s

B. 9.9 m/s

C. 14 m/s

D. 17 m/s

[1]

8. A horizontal piping system that delivers a

constant flow of water is constructed from

pipes with different diameters as shown in the

figure. At which of the labeled points is the

water in the pipe under the greatest pressure?

A. A

B. B

C. C

D. D [1]

9. The diagram represents a sphere under water. P, Q, R and S are forces acting on the sphere, due

to the pressure of the water. Each force acts perpendicularly to the sphere‟s surface. P and R act

in opposite directions vertically. Q and S act in opposite directions horizontally.

Which information about the magnitudes of the forces is correct?

A. P < R and S = Q

B. P > R and S = Q

C. P = R and S = Q and P ≠ S

D. P = R and S = Q and P = S [1]

10. Liquid flows through a 4.0 cm diameter pipe at 1.0 m/s. There is a 2.0 cm diameter restriction in

the line. What is the velocity in this restriction?

A. 2.0 m/s

B. 4.0 m/s

C. 0.25 m/s

D. 0.50 m/s [1]

10.0

15 m

QUESTIONS THAT REQUIRE SHORT ANSWER

11. Water is flowing at a rate of 2 m/s in a pipe of cross-sectional area 0.02 m2. If the cross-section

is reduced to half, then find the rate of flow.

_________________________________________________________________________ [2]

12. The diagram shows the velocity–time graph for an object.

Draw a position-time graph by the object in 8.0 s

[2]

13. (a) Calculate the absolute pressure at an ocean depth of 1000 m. Assume that the density of

water is 1000 kg/m3 and that Po= 1.01 x 10

5 Pa (N/m

2).

_________________________________________________________________________

[1]

b) Calculate the total force exerted on the outside of a 30.0 cm diameter circular submarine window

at this depth.

_________________________________________________________________________ [1]

14. Water flows through a pipe of diameter 8.0 cm with a speed of 10.0 m/s. It then enters a

smaller pipe of diameter 3.0 cm. What is the speed of the water as it flows through the

smaller pipe?

_________________________________________________________________________ [2]

15. Prove by experience that a fluid is incompressible

_________________________________________________________________________ [2]

16. Calculate the magnitude of the resultant force in each case below.

a

b

[2] [3]

17. The diagram shows a sealed container filled with air

and attached to a manometer. The liquid in the

manometer has a density of 1200 kg m−3

.

Atmospheric pressure is 1.02 105 Pa.

Calculate the pressure of the air inside the sealed container.

[3]

18. An object has a uniform acceleration a. After a time t its final velocity is v.

a Sketch a graph of velocity against time for this object. [3]

b Show that the displacement of the object in this time is given by:

2

2

1atvts [2]

19. In an experiment to determine the acceleration of free fall g, the period of oscillation T and

length l of a simple pendulum were measured. The uncertainty in the measurement of l is

estimated to be 4%, and the uncertainty in the measurement of T is estimated to be 1%. The

value of g is determined using the formula

4

What is the uncertainty in the calculated value for g? [2]

20. The pipe at A has a cross-sectional area of 1.3 10-4

m2 and supplies a fountain that is 0.50

meters above it at ground level as shown. The opening at point B has a cross-sectional area of

0.50 10-4

m2 and the water flows from this point at 2.2 m/s. Use water = 1000 kg/m

3 and g =

9.8 m/s2.

a) Calculate the speed of the water in the pipe below

the ground at point A. [2]

b) Calculate the absolute water pressure in the pipe at

point A.

[2]

QUESTIONS THAT REQUIRE AN EXTENDED ANSWER

21. The table below shows the time taken (t) and the displacement (s) of a trolley rolling down a

ramp.

Time / s 0 0.1 0.2 0.3 0.4 0.5 0.6

Displacement / 10−2

m 0 0.8 3.0 6.8 12.0 18.9 27.0

a) Plot a graph of displacement against time. (Make sure that you sketch a smooth curve.)

[1]

b) Describe the motion of the trolley. Explain your answer. [1]

c) Find the acceleration a of the trolley.

[1]

d) Determine the velocities of the trolley at times 0.2 s and 0.5 s:

[2]

22. The water supply of a building is fed through a main pipe that is 6.0cm in diameter. A 2.0 cm

diameter faucet tap is positioned 2.00 m above the main pipe and can fill a 2.510-2

m3 container

in 30.0 s. What is the gage pressure in the main pipe (difference in pressure)?

[4]

23. a. Distinguish between scalars and vectors.

[1]

b. A force of 7.5 N acts at 40° to the horizontal, as shown in Fig. 1.1.

Calculate the component of the force that acts

(i) horizontally,

horizontal component = ............................................. N

[1]

(ii) vertically.

vertical component = ............................................. N [1]

c. Two strings support a load of weight 7.5 N, as shown in Fig. 1.2.

One string has a tension T1 and is at an angle 50° to the horizontal. The other string has a tension T2

and is at an angle 40° to the horizontal. The object is in equilibrium.

Determine the values of T1 and T2 by using a vector triangle or by resolving forces.

T1 = .................................................. N

T2 = .................................................. N

[5]

24. During the testing of a car, it is timed over a measured kilometer. In one test it enters the timing

zone at a velocity of 50 m/s and decelerates at a constant rate of 0.80 m/s2

(a) the velocity of the car as it leaves the measured kilometer

[2]

(b) the time it takes to cover the measured kilometer

[2]

Mark scheme for the term 1

Tas

k

Answer Ma

r

k

Addition

al

infor

matio

n

1 B 1

2 C 1

3 D 1

4 B 1

5 C 1

6 A 1

7 B 1

8 A 1

9 A 1

10 B 1

11 S1v1=S2v2

4m/s

1

1

12 correctly reads equation/All calculations are correct

Axes are correctly labelled with quantity/plots the right

1

1

13 (a) 9.9 106

N/m2,

(b) 2.8 106 N

1

1

14 71 m/s 2

15

correctly answers

An incompressible fluid is a fluid that does not change the volume of the

fluid due to external pressure

2

16 a) R

2 = 7.0

2 + 5.0

2

R = 2549 = 8.6 N

b) Force vertically = 40 10 = 30 N and

force horizontally 80 20 60 N

R2 = 30

2 + 60

2 N 673600900 R [1]

1

1

1

1

1

17 P hρg 0.48 1200 9.81

P 5650 5700 Pa

Pressure in container 102 000 – 5650 96 350 96 000 Pa

1

1

1

18 a)

Line of positive slope

Correct labels on axes

1

1

1

b) s = area under the graph

s = area of „larger‟ rectangle − area of shaded triangle

tvvts )(2

1

Δv = at

hence 2

2

1)(

2

1atvttatvts

1

1

19 𝜀

+ 2

Answer: 6%

1

1

20 𝐴 ∙ 𝑣 𝐴 ∙ 𝑣

𝑣 0.846 𝑚/𝑠

𝑃 + ℎ +

𝑃 + ℎ +

𝑃 1.08 × 10 Pa

1

1

1

1

21 a) Correct plotting of points. A smooth curve through all the data points. 1

b) The trolley is accelerating.The gradient of the graph (which is velocity)

increases with time.

1

c) 𝑎 1.5 ms-2

1

d) At 0.2 s: velocity u 0.30 m s−1 (within ± 0.05 m s−1)

At 0.5 s: velocity v 0.75 m s−1 (within ± 0.07 m s−1)

1

1

22 𝑣 2.65 𝑚/𝑠

𝑣 𝐴 ∙ 𝑣 𝐴

0.29 𝑚/𝑠

𝑃 + ℎ + 𝑣

2 𝑃 + ℎ +

𝑣

2

𝑃 − 𝑃 2.32 × 10 𝑃𝑎

1

1

1

1

23 a) scalar has magnitude/size, vector has magnitude/size and direction

b) i) horizontally: 5.74 N

ii) vertically: 4.82 N

c) correct labelling of two forces, three arrows and two angles

T2 cos40° = T1 cos50°

T1 sin50° + T2 sin40° = 7.5

T1 = 5.74 N

T2 = 4.82 N

1

1

1

1

1

1

1

1

(allow ± 0.2 N for scale diagram)

24 a) Required equation: v

2 = u

2 + 2as

Substitute the relevant values and solve the equation: v2 = 50

2 + 2 ×

(−0.80) × 1000 = 2500 − 1600 = 900

v = 30 m/s

b) Required equation: v = u + at

Substitute in the relevant variables:

30 = 50 − (0.80 × t)

t = (50 − 30)/0.8=25 s

1

1

1

1

Total: 60




1. A body of mass 𝑚, moving at velocity 𝑣, collides with a stationary body of the same mass and

sticks to it. Which row describes the momentum and kinetic energy of the two bodies after the

collision?

momentum Kinetic energy

A mv 1/4 mv2

B mv 1/8 mv2

C 2 mv 1/2 mv2

D 2 mv mv2

[1]

2. A molecule of mass m travelling horizontally with velocity u hits a vertical wall at right angles to

its velocity. It then rebounds horizontally with the same speed. What is its change in momentum?

A. zero

B. mu

C. -mu

D. -2mu

[1]

3. A long, thin metal wire is suspended from a fixed support and hangs vertically. Masses are

suspended from its lower end. The load on the lower end is increased from zero and then decreased

again back to zero. The diagram shows the force-extension graph produced

Where on the graph would the elastic limit be found?

A. anywhere between point R and point S

B. beyond point S but before point T

C. exactly at point S

D. exactly at point T

[1]

4. Two spheres travel along the same line with velocities u1 and u2. They collide and after collision

their velocities are v1 and v2.

Which collision is not elastic?

/ms-1 /ms

-1 𝑣 /ms

-1 𝑣 /ms

-1

A 2 -5 -5 -2

B 3 -3 0 6

C 3 -2 1 6

D 5 2 3 6

[1]

5. Four solid steel rods, each of length 2.0 m and cross-sectional area 250 mm2, equally support

an object weighing 10 kN. The weight of the object causes the rods to contract by 0.10 mm.

What is the Young modulus of steel?

A. 2.0 × 108

N m–2

B. 2.0 × 1011

Nm–2

C. 8.0 × 108

N m–2

D. 8.0 × 1011

Nm–2

[1]

6. What is the ultimate tensile stress of a material?

A. the stress at which the material becomes ductile

B. the stress at which the material breaks

C. the stress at which the material deforms plastically

D. the stress at which the material reaches its elastic limit

[1]

7. Which force-extension graph shows plastic deformation of a sample of material?

[1]

8. What is a correct statement of the principle of conservation of momentum?

A in an inelastic collision the total kinetic energy and momentum are constant

B in any collision the total momentum of an isolated system is constant

C in any isolated system the force on a body equals the rate of change of momentum

D momentum is constant when mass and velocity are constant

[1]

9. The system comprises three masses: m, 2m, 3m. The distances between the masses are identical

and equal to R. The system is 'broken' in such a way that the masses are moved an infinite

distance apart from one another. Indicate in which case the amount of work done is lowest.

A. When the smallest mass, m, is moved away to an infinite distance first.

B. When the greatest mass, 3m, is moved away to an infinite distance first.

C. When masses are moved away simultaneously in such a way that the distances between them

increase (R increases).

D. The order in which the masses are moved away is of no importance. [1]

10. What data do you need to calculate the orbital speed of a satellite?

A. mass of satellite, mass of planet, radius of orbit

B. mass of satellite, radius of planet, area of orbit

C. mass of satellite and radius of orbit only

D. mass of planet and radius of orbit only [1]


11. Two stars each of mass M are separated by a distance 2a. The stars revolve around a common

centre as shown.

Show that the speed of each of the masses is given by v GM

4a.

[2]

12. Complete the table

Definition Characteristics/

Conditions

Examples/

Models

Non - examples

Elastic

deformati

on

Plastic

deformati

on

[3]

13. A student is given a wire made of an unknown metal and asked to determine its Young‟s

Modulus. The student uses a caliper Vernier scale to measure the wire‟s extension under a range

of loads. Results are shown below.

Load (N) Extension (10-3

m)

5.0 0.9

10.0 1.6

15.0 2.2

20.0 2.8

25.0 3.4

30.0 4.0

(i) Plot a graph of load against extension (use the grid provided).

(ii) Given that the wire‟s diameter is 1.12 mm and its non-stretched length is 2.060 m, find the

Young‟s Modulus of the metal.

[4]

14. A ball of mass 210 g moving at a speed of 23 m/s hits a wall at right angles and rebounds

at the same speed. The ball is in contact with the wall for 0.31 s.

a) Calculate the change in momentum of the ball. [2]

b) Is the momentum of the ball conserved? Explain your answer. [2]

c) Calculate the magnitude of the average force acting on the ball. [2]

15. Calculate the escape speed from the Earth for a 5000 kg spacecraft, and determine the kinetic

energy it must have at the Earth‟s surface in order to move infinitely far away from the Earth

(RE=6400 km, MЕ=5.971024

kg, G=6.6710-11

Nm2kg

-2)

[2]

16. The moon orbits 384 400 km above the surface of the earth. (G = 6.67 10-11

Nm2

/kg2, rearth =

6400 km, Mearth = 5.97 1024

kg, rmoon = 1737 km, mmoon = 7.34 1022

kg)

a) What is the moon‟s orbital velocity? [1]

b) At this velocity, how long does it take the moon to orbit the earth? [1]

17. A cannon of mass 850 kg fires a 20 kg shell at a velocity of 180 m s−1

. Calculate the final

momentum of the shell. [2]

18. Indicate the graph that represents the relationship between potential energy and distance from

the centre of the Earth.

[1]

19. A spring has a natural length of 2.5 cm. A force of 4.0 N extends the spring to a length of

6.2 cm.

a. What is the extension of the spring? [1]

b. Determine the force (spring) constant k for the spring in N m−1

. [1]

c. Calculate the extension of the spring when a tensile force of 6.0 N is applied. You may

assume that the spring has not exceeded its elastic limit. [1]

20. The diagram below shows the initial state of two trolleys A and B before colliding and the

final state immediately after the collision.

Calculate the final velocity v of trolley B. [3]

21. (a) Advantages of geostationary satellites:

___________________________________________________________________________ [1]

(b) Disadvantages of geostationary satellites:

___________________________________________________________________________ [1]

(c) Determine the typical orbital radius of a geostationary satellite around Earth. (Given: mass of

Earth = 6.0 x 1024

kg) [2]

(d) Would a geostationary satellite that orbit around planet Mars be at the same distance

(= 4.2 107 m), as example (a)? Why? [1]

22. When holding a hose fire fighters need to ensure that they are not pushed backwards, especially

if the water is ejected at a high speed. 20 kg of water is ejected horizontally in 10 s;

The speed of the water leaving the nozzle is 30 m s–1

.

Calculate the force experienced by a fire fighter holding the hose.

[2]


23. A student investigated the stretching of a spring by hanging various weights from it and

measuring the corresponding extensions. The results are shown below.

(a) On Fig1, plot the points from these results. Do not draw a line through the points yet. [2]

(b) The student appears to have made an error in recording one of the results.

Which result is this?

[1]

(c) Ignoring the incorrect result, draw the best straight line through the remaining points.

[1]

(d) State and explain whether this spring is obeying Hooke‟s Law.

[2]

(e) Describe how the graph might be shaped if the student continued to add several more weights to

the spring.

[1]

(f) The student estimates that if he hangs a 45 N load on the spring, the extension will be 920 mm.

Explain why this estimate may be unrealistic.

[1]

24. (a) Define gravitational potential at a point

_________________________________________________________________________ [1]

(b) The gravitational potential at distance from point mass is given by the expression

−

Where G is the gravitational constant.

Explain the significance of the negative sign in this expression

_________________________________________________________________________ [2]

(c) A spherical planet may be assumed to be an isolated point mass with its mass concentrated at its

Centre. A small mass m is moving near to, and normal to, the surface of the planet. The mass

moves away from the planet through a short distance h.

State and explain why the change in gravitational potential energy ΔEP of the mass is given by the

expression

𝑚 ℎ

where g is the acceleration of free fall.

___________________________________________________________________________[2]

(d) The planet has mass =2×1026

kg and diameter 6.8 × 103

km.

The product for this planet is 4.3 × 10-13

N m2 kg

–1.

A rock, initially at rest a long distance from the planet, accelerates towards the planet. Assuming

that the planet has negligible atmosphere, calculate the speed of the rock as it hits the surface of

the planet.

speed=____________m/s [2]


Tas

k

Answer Mar

k

Additional

informa

tion

1 A 1

2 D 1

3 B 1

4 A 1

5 D 1

6 B 1

7 D 1

8 B 1

9 D 1

10 D 1

11 relating the gravitational force to the centripetal acceleration it causes;

2 2

2(2 )

GM Mv

aa

1

1

12 The student correctly write the definition of the term

The student correctly name the conditions and characteristics of the

phenomenon

The student correctly distinguish the example and non-examples

1

1

1

13 Student correctly draw the graph

Student correctly calculates the work done by gravity in extending the

spring by the above extension.

/ 𝐴 From the straight part of the graph,

/ = 10 / (1.6 × 10-3

) = 6250 Nm-1

𝐴 = π × (0.56 × 10-3

) 2 = 9.9 × 10

-7 m

2

= 6250 × 2.060 / (9.9 × 10-7

) = 1.3 × 1010

Pa

1

1

1

1

14 a) Δp mΔv 0.210 (–23 – 23) (original direction taken as

„positive‟)

Δp –9.66 kg m s–1

–9.7 kg m s–1

(The minus implies that the

force exerted by the wall on the ball is in the opposite direction

to its initial direction of travel.)

b) The momentum of the ball itself is not conserved.

The total momentum of the wall and the ball is conserved. The wall

gains momentum equal

to 9.7 kg m s–1 but because it is massive its velocity is negligible.

c) F t

p

Δp –9.66 kg m s–1

, Δt 0.31 s

F 31.0

66.9 (magnitude only) F 31 N

1

1

1

1

1

1

15

v √2GM R

1.1210 m/s

KE 1

2mv

3.1410 J

1

1

16 a) ≈1010 m/s

b) 28.3 days or 2.45106

s

1

1

17 p mv 20 180

p 3.6 103 kg m s

–1

1

1

18 3 1

19 a) Extension 6.2 2.5 3.7 cm

b) 11 m N 110m N 108 k

c) cm) (5.6 m 106.5 2x

1

1

1

20 initial momentum final momentum

(1.2 4.0) (0.80 (–2.5)) (1.2 1.0) (0.80 v)

2.80 1.20 0.80v

v 80.0

20.180.2 v 2.0 m s

–1 to the right

1

1

1

21 a) A geostationary satellite is ideal for telecommunication purposes

since it remains „stationary‟ above the same spot on the Earth‟s

surface at all times/ they are ideal for meteorological applications

and remote imaging.

b) fuzzy image/the transmitting stations in countries positioned at

latitudes higher than 60 degrees may not be able to receive strong

signals from geostationary satellites, as the signals would have to

pass through a large amount of atmosphere. This is true for

countries beyond the 60 degrees latitude „belt‟, both on north and

south sides.

c) 2

2 T

π2mr

r

GMm

32

32

2

ππ

GMTr

4

))(8.64x10)(6.0x10(6.67x10

4

242411

r = 4.2 x 107 m (about 6.6 times of Earth‟s radius)

d) No, because the period of rotation and mass of planet Mars are not

the same as Earth‟s.

1

1

1

1

1

22

.N60

sm30s10

kg20 1

F

vt

m

t

pF

1

1

23 (a) 5 points correctly plotted ±½ small square –1 e.e.o.o. (Each Error

Or Omission) (ignore 0,0)

(b) 3 N

(c) good straight line through origin and candidate‟s remaining points

(d) straight line / constant gradient

does obey Hooke‟s Law

(e) graph becomes non-linear / curves / bends

Ignore reference to direction of curve or bend.

(f) will have exceeded / reached proportional / elastic limit

OR permanently deformed OR will have broken OR no longer elastic

1

1

1

1

1

1

1

1

24 (a) work done in bringing unit mass from infinity (to the point) 1

(b) gravitational force is (always) attractive

either as decreases, object/mass/body does work

or work is done by masses as they come together

1

1

(c) either force on mass = mg (where g is the acceleration of free fall

/gravitational field strength) g=GM/R2

∆EP = force × distance moved

𝑚 ℎ / 𝑚 / 𝑚(

−

)

If then ( − ) ℎ and

𝑚 ℎ

1

1

(d)

𝑚𝑣 𝑚

𝑣=5.0×103

m/s

1

1

Total: 60




1. A mechanical system is oscillating at resonance with constant amplitude. Which one of the

following statements is not correct?

A. The applied force prevents the amplitude from becoming too large.

B. The frequency of the applied force is the same as the natural frequency of oscillation of the

system.

C. The total energy of the system is constant.

D. The amplitude of oscillations depends on the amount of damping. [1]

2. A simple pendulum with a length of 1 m oscillates on the surface of a hypothetical planet X.

What is the surface gravity on the planet if the period of oscillations is 4 s?

A. 1.6

B. 3.7

C. 11.2

D. 2.46

[1]

3. An object undergoes SHM and position as a function of time is presented by the following

formula: x= 0.10sin (4πt) m. What is the period of oscillations?

A. 2 s

B. 0.1 s

C. 0.5 s

D. 4 s [1]

4. The position as a function of time of a mass-spring oscillating system is presented by the graph.

Which of the following is true about velocity and acceleration at the time 1.5 s?

Velocity Acceleration

A. v > 0 a < 0

B. v = 0 a > 0

C. v < 0 a = 0

D. v >0 a = 0

[1]

5. An object oscillates at the end of a spring. The position as a function of time is presented by the

graph. Which of the following formulas represent the position and velocity of the object?

Position Velocity

A. x = (0.5) Sin(πt) v = (0.5π) Sin(πt)

B. x = (0.5) Sin(πt) v = (0.5π) Cos(πt)

C. x = (0.5) Cos(πt) v = (0.5π) Sin(πt) D. x = (0.5π) Sin(πt) v = (0.5) Sin(πt) [1]

6. In the kinetic model of an ideal gas, it is assumed that:

A. The forces between the gas and the container are zero

B. The intermolecular potential energy of the molecules of the gas is constant.

C. The kinetic energy of a given gas molecule is constant

D. The momentum of a given molecule of the gas is constant

[1]

7. A gas molecule of mass m moving at velocity u collides at right angles with the side of a

container and rebounds elastically. Which one of the following statements concerning the motion

of the molecule is incorrect?

A. The magnitude of the change in momentum of the molecule is zero.

B. The magnitude of the change in momentum of the molecule is 2 mu.

C. The force exerted by the molecule on the side of the container is equal to the force exerted by the

container on the molecule.

D. The change in kinetic energy of the molecule is zero. [1]

8. The gas in a 600 mL balloon has a pressure of 1.20 atm. If the temperature remains constant,

what will be the pressure of the gas in the balloon when it is compressed to 400 mL?

A. 0.80 atm

B. 1.2 atm

C. 1.8 atm

D. 3.0 atm

[1]

9. The graph shows the average power delivered

to an oscillating system as a function of the

driving frequency. According to these data

A. the resonant frequency is greater than ω0

B. the system corresponding to curve 1 has the

smallest quality factor

C. the system corresponding to curve 4 has the

smallest quality factor

D. the resonant frequency is less than ωo

[1]


10. The Sears Tower was designed to dampen the energy from the windy city‟s wind so that the

period of the top is in minutes, rather than seconds and its amplitude is small. Why?

[1]

11. A gas thermometer measures temperature by measuring the pressure of a gas inside the fixed

volume container. A thermometer reads a pressure of 248 kPa at 0˚C. What is the temperature

when the thermometer reads a pressure of 345 kPa?

[2]

12. This is the graph of displacement x against time t for an oscillating object.

Use the graph to determine the following:

a) the amplitude of the oscillation and period [1]

b) the frequency in hertz (Hz) [1]

c) the angular frequency in radians per second (rad s−1

). [1]

d) the maximum speed of the oscillating mass. [1]

13. A pendulum is pulled to the side and released. Its subsequent motion appears as follows:

a) At which of the above times is the kinetic energy a maximum? ____________________[1]

b) At which of the above times is the potential energy a maximum?___________________[1]

c) At which of the above times is kinetic energy being transformed to potential energy?

____________________________________________________________________[1]

d) At which of the above times is potential energy being transformed to kinetic energy?

____________________________________________________________________[1]

14. At standard temperature and pressure, bromine (Br2) is a red liquid. Bromine sublimes when

the temperature is –25 0C and the pressure is 101.3 kPa. The phase diagram for bromine is

shown below.

(a) Label each region of the graph as solid, liquid, or

gas. [1]

(b) Label the triple point, normal melting point, and

normal boiling point on the graph and estimate

their values in the spaces below. [3]

Normal Melting Point =

_________________________

Normal Boiling Point =

_________________________

Triple Point = _________________________

(c) Using arrows labeled „S‟, „V‟, and „M‟, label those portions of the phase diagram where

sublimation, vaporization, and melting occur, respectively.

[1]

15. A rigid cylinder of volume 0.030 m3 holds 4.0 g of air. The molar mass of air is about 29 g/mol.

a) Calculate the pressure exerted by the air when its temperature is 34 °C. [2]

b) What is the temperature of the gas in degrees Celsius when the pressure is twice

your value from part a? [2]

16. The efficiency of a Carnot engine is 30%. The engine absorbs 800 J of heat per cycle from a hot

temperature reservoir at 500 K.

Determine:

(a) the heat expelled per cycle

[3]

(b) the temperature of the cold reservoir

[1]

17. a) What is Dalton's law of partial pressure?

_______________________________________________________________________ [1]

b) Container (T) in the figure below contains a mixture of the three different gases in (a), (b),

and (c) at the pressures shown. Write in the pressure in container (T).

[1]

18. Two objects A and B have the same period of oscillation. In each case a and b below,

determine the phase difference between the motions of the objects A and B.

[2]

19. There is isoprocess in VT graph. Draw this process in PV

[2]

20. Use the kinetic theory of gases to explain why:

(a) the pressure exerted by an ideal gas increases when it is heated at constant volume [2]

(b) the volume occupied by an ideal gas increases when it is heated at constant pressure [2]

21. (a) The molecular theory model of an ideal gas leads to the derivation of the equation

⟨ ⟩

Explain what each symbol in the equation represents. [1]

(b) One assumption used in the derivation of the equation stated in part (a) is that molecules are in

state of random motion.

Explain what is meant by random motion. [1]

22. During an isothermal and an adiabatic transition the volume of a gas has halved. The initial

pressure and the volume of the gas were identical in both transitions. Mark the transition in

which the increase in pressure is greater.

[1]

3. EA - Questions that require an extended answer

23. A small toy boat is floating on the water‟s surface. It is gently pushed down and then

released. The toy executes simple harmonic motion. Its displacement–time graph

is shown here.

For this oscillating toy boat, calculate:

a) its angular frequency [2]

b) its maximum acceleration [2]

c) its displacement after a time of 6.7 s, assuming that the effect of damping on the boat is

negligible.

[2]

24. a) Calculate the mean translational kinetic energy of gas atoms at 0 °C. [2]

b) Estimate the mean speed of carbon dioxide molecules at 0 °C.

(The molar mass of carbon dioxide is 44 g.) [3]

c) Calculate the change in the energy of one mole of carbon dioxide gas when its temperature

changes from 0 °C to 100 °C. [3]


Tas

k

Answer Mar

k

Additional

inform

ation

1 A 1

2 D 1

3 C 1

4 D 1

5 B 1

6 B 1

7 A 1

8 C 1

9 C 1

10 explains of resonance where it is useful, and where it is not 1

11 𝑃 𝑃

380 K

1

1

12 a) Amplitude 0.10 m Period 4.0 10–2

s

b) f T

1

04.0

1 f 25 Hz

c) ω 2πf 2π 25 ω 157 rad s–1

160 rad s–1

d) Maximum speed 10.0157A

maximum speed 15.7 m s−1

16 m s−1

1

1

1

1

13 a) C, G

b) A,E,I

c) D,H

d) B,F

1

1

1

1

14

(a), (c)

(b) Normal Melting Point = -7.0°C

Normal Boiling Point = 58.5°C

Triple Point = -8°C and 6 kPa

1

1

1

1

1

15 a) PV nRT n

29

0.4 0.138 moles

P V

nRT

030.0

)34273(31.8138.0

P 1.17 × 104 Pa = 1.2 × 10

4 Pa (12 kPa)

1

1

b) T

P is constant when the volume of the gas is constant.

The pressure is doubled, hence the absolute temperature of the gas is

also doubled.

Therefore:

temperature 2 × (273 + 34) 614 K

temperature in °C 614 – 273 341 °C

1

1

16

−

1

1

1

1

17 The total pressure of a mixture of gases is equal to the sum of the

partial pressures of the component gases.

PressureTotal = PressureGas 1 + PressureGas 2 + PressureGas 3

1

1

18 Phase difference 2π

T

t

where T is the period and t is the time lag between the motions of

the two objects.

phase difference 2π

T

t 2π

10

5.2

phase difference 2

π 1.6 rad

1

1

19 correctly drawn a diagram

1-2 V=const

2-3 T=const

3-4 T=const

4-1 V=const

2

20 a) When the gas is heated the average speed of molecules increases.

therefore there are more collisions (with the wall) per second and

more momentum change per collision. This results in a greater force

per unit area on the container walls (greater pressure) because there

is an increase in momentum change per second producing a greater

force (Ft = p).

2

KT

T

T

Te

JQ

QWQQW

JW

J

W

Q

We

C

C

H

CC

C

CCH

H

350

500130.01

560

800

240

80030.0

b) When the gas is heated the average speed of molecules increases.

The faster molecules would result in more momentum change per

collision, increasing the pressure, if the volume was kept constant.

However if the volume was greater, there would be fewer collisions

per second. Therefore to maintain a constant pressure the volume of

the gas must increase when the gas is heated.

2

21 a) p: pressure and V: volume

N: number of molecules m: mass of one molecule/particle/atom

⟨ ⟩ Mean square speed

b) When molecules are in state of random motion they have a range of

speeds and they have no preferred direction of movement

1

1

22 2 graph 1

23 a) ω 2πf

T

π2

2.0

π2

ω 3.14 rad s–1

3.1 rad s–1

b) a –(2πf )2x or a –ω

2x

a 3.142 3.0 10

–2

a 0.30 m s–2

c) x A cos(2πft) A cos (ωt)

x 3.0 10–2

cos(3.14 6.7) –1.7 10–2

m

1

1

1

1

1

1

24 a) Mean kinetic energy kT

2

3

Mean kinetic energy= 5.65 10–21

J 5.7 10–21

J

b) There are 6.02 1023

molecules of carbon dioxide.

mass of molecule 26

231031.7

1002.6

044.0

kg

212 1065.52

1 mv J

26

21

1031.7

1065.52

v

speed 393 m s–1

390 m s–1

c) Total kinetic energy of one mole of gas for carbon dioxide

kT2

6NA RT

2

6

(Note: R k NA)

For an ideal gas, the change in energy is entirely kinetic energy.

Change in energy 10031.82

6)273373(

2

6R

change in energy 2.493 kJ 2.5 kJ

1

1

1

1

1

1

1

1

Total: 60




1. Which of the statements about stationary waves is true?

A. Anode occurs where the vibration is at a maximum

B. An antinode occurs where the vibration is at a maximum

C. The distance between consecutive antinodes is one wavelength

D. The distance between consecutive nodes is one wavelength

[1]

2. The diagram shows the fundamental mode of vibration on a string. The string is vibrating with a

frequency of 60 Hz.

Which diagram shows the second harmonic, with the correct frequency of vibration?

A

[1]

3. The diagram shows the apparatus used to measure the wavelength of microwaves.

As a detector is moved from the transmitter to the metal plate, maxima are found at points

P, Q, R, S and T. What is the wavelength of the microwaves?

A. 4 cm

B. 5 cm

C. 10 cm

D. 40 cm [1]

4. Two waves having the same frequency and amplitude are traveling in the same medium.

Maximum constructive interference occurs at points where the phase difference between the two

superposed waves is

A. 00

B. 900

C. 1800

D. 2700 [1]

frequency = 30 Hz

frequency = 20 Hz

frequency = 120 Hz

frequency = 180 Hz

A B

C D

5. A beam of monochromatic light approaches a barrier having four

openings, A, B, C, and D, of different sizes as shown below.

Which opening will cause the greatest diffraction? A. A

B. B

C. C

D. D

[1]

6. A contact lens is made of plastic with an index of refraction of 1.50. The lens has an outer radius

of curvature of +2.00 cm and an inner radius of curvature of +2.50 cm. What is the focal length

of the lens?

A. 20.0 mm

B. 20.0 cm

C. -20.0 mm

D. -20.0 cm [1]

7. The prism totally reflects some wavelengths of light as shown, but other

wavelengths pass through. The index of refraction of this prism for the

longest wavelengths that are totally reflected is approximately

A. 1.50

B. 1.53

C. 1.46

D. 1.41

[1]

8. You place a point source of light at the bottom of a pool of water 1.00 m deep.

The source emits rays upward in all directions. You notice that a circle of light is formed by the rays

that are refracted into the air and that the rays outside of this circle are reflected back into the

water. The index of refraction of water is 1.33. The radius R of the circle at the surface of the

water is approximately

A. 0.75 m

B. 1.00 m

C. 1.13 m

D. 1.33 m

[1]

9. When an object is closer to a concave mirror than the mirror's focal point, the

A. magnification is less than one

B. image distance is greater than the object distance

C. magnification is equal to one

D. image distance is negative [1]

10. A vibrating tuning fork, held above a tube, sets up a standing wave in the air in the tube.

Which of the following statements is correct?

A. At the antinodes the particles vibrate back and forth, parallel to the length of the tube.

B. At the antinodes the particles vibrate from side to side, perpendicular to the length of the tube.

C. At the nodes the particles vibrate back and forth, parallel to the length of the tube.

D. At the nodes the particles vibrate from side to side, perpendicular to the length of the tube.

[1]


11. A microwave source is directed towards a metal plate with two narrow vertical slits. A receiver

is slowly moved along the line XY as shown in the diagram.

a) Explain why the receiver registers a series of maxima and minima. [3]

b) The wavelength of the microwaves is 2.8 cm. The separation between the slits is 4.0 cm

and the receiver is a distance of 80 cm from the slits. Calculate the separation between

adjacent maxima. [1]

c) Describe the effect on your answer to b when:

i) the separation between the slits is halved [1]

ii) the distance between the slits and the receiver is doubled. [1]

12. The diagram below shows an arrangement used to demonstrate the interference of water waves.

a) Constructive interference occurs at point A. What is the path difference of the waves from

the gaps S1 and S2? [1]

b) The water waves have a wavelength of 3.0 cm. Determine the path difference for

the waves arriving at point B. Name the type of interference taking place at this point. [3]

13. If a yellow light with a wavelength of 540 nm shines on a double slit with the slits cut 0.01 mm

apart, determine what angle you should look away from the central fringe to see the second order

fringe?

[2]

14. A light ray strikes a homogeneous rectangular block of glass of thickness w at an angle i. The

ray emerges at point B at an angle i'.

a) Find i' in terms of i and show that the emerging and incident rays are parallel. [2]

b) Find the lateral displacement which is the distance d between the incident and emerging rays

in terms of angle i, the refractive indices n1and n2 and width w of the block. [1]

c) Use the formula obtained in part b) to calculate d for n1 = 1, n2 = 1.55, w = 3 cm and i = 32°.

[1]

15. What is Huygens' Principle?

________________________________________________________________________________

_____________________________________________________________________________

[1]

16. a) List the various types of aberrations

b) What causes them and how can each be reduced? [3]

17. A thin symmetric lens provides an image of a fingerprint with a magnification +0.2 when the

fingerprint is 1 cm farther from the lens than the focal point of the lens. What is the type of the

image, and what is the type of the lens?

[2]

18. The diagram shows a stationary wave on a string.

a) Mark the positions of the nodes (N) and the antinodes (A). [1]

75 cm

b) Explain what is meant by a node and an antinode. [1]

c) Determine the wavelength of the progressive waves on the string. [1]

19. A convex mirror whose radius of curvature is 30 cm forms an image of a real object, which has

been placed 20 cm from the mirror. Draw the ray diagram to show location of the image

produced by the convex mirror. Calculate the position of the image; describe its characteristics

and the magnification produced.

[6]

20. A glass converging lens has one flat side and another with a radius of 20 cm. What is the focal

length of the lens? (The index of refraction of the glass in the lens is 1.50)

[2]

21. Explain what is meant by coherent sources.

[1]

22. A two lens magnifying system uses lenses of focal lengths 2.5 and 9.5 cm for the objective and

eyepiece respectively. The two lenses are positioned 23 cm apart. An object for study is placed

3.0 cm in front of the objective lens. Find the position of the final image relative to the eyepiece

lens.

[2]


23. Given the above lens system and data:

d0 = 50 cm, d= 10 cm, L1 focal length (f1) = 30 cm, L2 focal length (f2) = 20 cm.

Find:

1) Where is the first image formed: di1 = ________________________________________[1]

2) This first image will now serve as the object for the second lens. How far is it located in front of

the second lens: do2 = ______________________________________________ [1]

3) Where is the image formed by the second lens: di2 = ____________________________ [1]

4) What is the final magnification for this system of lenses: M = _____________________[1]

5) The final image of this system is : __________, ____________, ________ [1]

24. Answer the following questions with supporting calculations.

You are given a diffraction grating with 40 lines per mm.

a) The diffraction grating is mounted on an instrument that can measure angles to within 0.1°. Can

this instrument be used to determine the individual wavelengths of spectral lines of wavelengths

589.6 nm and 589.0 nm? [5]

b) White light is incident normally at the grating. Estimate the angle between the extreme

ends of the spectrum for the tenth-order maxima. [4]


Tas

k

Answer Mar

k

Additional

informat

ion

1 B 1

2 D 1

3 C 1

4 A 1

5 A 1

6 B 1

7 D 1

8 C 1

9 D 1

10 B 1

11 a) The microwaves are diffracted at the two slits.

Beyond the slits, the waves interfere. A maximum signal is

registered when the waves

interfere constructively.

A minimum signal is registered when the waves interfere

destructively.

b) D

ax x

0.4

808.2

a

D x 56 cm

c) i) x aa

D 1

; hence as a is halved, x is doubled (112 cm).

ii) x Da

D

; hence as D is doubled, x is doubled (112

cm).

1

1

1

1

1

1

12 a) The path difference is equal to a whole number of wavelengths.

b) Path difference S1B S2B

path difference 15.5 14.0 1.5 cm

The path difference is 2

, so destructive interference takes place at

B.

1

1

1

1

13 d sinθ = nλ

θ=6.200

1

1

14 a) Snell's at point A: 𝑠 𝑠 Snell's law at point B: n2 sin k = n1 sin i'

The normals NA and NB to the interfaces at A and B are parallel

to each other and therefore angles j and k are equal. Hence

n1 sin i = n2 sin j = n2 sin k = n1 sin i'

Therefor i'= i

The incident and emerging have equal angles with the normals

therefore the emerging and incident rays are parallel.

b) d = w sin(i - j) / cos j

where j = arcsin [ (n1/n2) sin i ]

c) 0.66 cm 0.7 cm

1

1

1

1

15 Every point of a wave front may be considered the source of

secondary wavelets that spread out in all directions with a speed

1

equal to the speed of propagation of the waves.

16 Chromatic Aberration and Spherical Aberration

Chromatic Aberration: In the human eye, chromatic aberration is

reduced by the lens, which changes index from the nucleus

outward.

Spherical aberration in the human eye is reduced by the aspheric

shape of the lens and the cornea

1

1

1

17 Image is erect and virtual;

this is diverging lenses

1

1

18

a) The nodes (N) are shown correctly.

The antinodes (A) are shown correctly.

b) A node is a point of zero amplitude.

An antinode is a point of maximum amplitude

c) There are three complete „loops‟ on the string, so = 3

2 length of

the string.

= 3

2 75 cm = 50 cm

1

1

1

19 Student correctly draw the ray diagram to show location of image

produced by the convex mirror

Student correctly define the distance between mirror and object +20

cm, radius of curvature -30 cm ( as convex mirror)

Student correctly write the formula for mirror

+

Student correctly gives the answer for distance for image f = -8,6 см

Student correctly describe the characteristics of image - virtual,

reduced, upright

Student correctly determine the magnification of mirror 3/7= 0,43

1

1

1

1

1

1

20

f=40 cm

1

1

21 Coherent sources emit waves with a constant phase difference. 1

22 –50.7 cm 2

23 Student correctly determine the first image distance: di1 = 75 cm

Student correctly determine how far is it located in front of the

second lens: do2 = - 65 cm ( as first image – second object is back

of the lens system)

Student correctly determine the second image distance: di2= 15.3 cm

Student correctly determine the final magnification for this system of

lenses: M = - 0.35

Student correctly describe image: real, inverted and reduced relative

1

1

1

1

cmcmf 40

1

20

1015.1

1

to original object 1

24

a) 40

100.1 3d d 2.5 10

5 m

The longer wavelength will give the larger angle . Hence:

9

5

max106.589

1105.290sin

dn nmax 42.4 Hence nmax 42

(integer).

For 589.0 nm 5

9

105.2

100.58942sin

d

n . Hence 81.7°

For 589.6 nm 5

9

105.2

106.58942sin

d

n . Hence 82.1°

The difference between the angles 82.1° 81.7° ≈ 0.4°. This is

greater than 0.1°,

so it is possible to measure the wavelengths separately.

b) The wavelength of visible light lies in the range 400 nm

(violet) to 700 nm (red).

For 400 nm 5

9

105.2

1040010sin

d

n . Hence 9.21°

For 700 nm 5

9

105.2

1070010sin

d

n . Hence 16.26°

Difference between the angles 10.26° 9.21° 7°.

1

1

1

1

1

1

1

1

1

Total: 60

GRADE 12


Tasks for the Internal Summative Assessment for the term 1


1. Which list shows electromagnetic waves in order of increasing frequency?

A. radio waves → gamma rays → ultraviolet → infra-red

B. radio waves → infra-red → ultraviolet → gamma rays

C. ultraviolet → gamma rays → radio waves → infra-red

D. ultraviolet → infra-red → radio waves → gamma rays

[1]

2. Which one of the following statements concerning the wavelength of an electromagnetic wave in

a vacuum is true?

A. The wavelength is inversely proportional to the speed of the wave.

B. The wavelength is the same for all types of electromagnetic waves.

C. The wavelength is directly proportional to the frequency of the wave.

D. The wavelength is inversely proportional to the frequency of the wave.

[1]

3. The Y-input terminals of a cathode-ray oscilloscope (c.r.o.) are connected to a supply of

amplitude 5.0V and frequency 50Hz. The time-base is set at 10ms per division and the Y-gain at

5.0V per division.

Which trace is obtained?

[1]

4. Amplitude modulation is

A. Change in amplitude of the carrier according to modulating signal

B. Change in frequency of the carrier according to modulating signal

C. Change in amplitude of the modulating signal according to carrier signal

D. Change in amplitude of the carrier according to modulating signal frequency

[1]

5. In an AM wave useful power is carrier by ………….

A. Carrier

B. Sidebands

C. Both sidebands and carrier

D. None of the above

[1]

6. Calculate the power in one of the side band in SSBSC modulation when the carrier power is

124W and there is 80% modulation depth in the amplitude modulated signal.

A. 89.33 W

B. 64.85 W

C. 79.36 W

D. 102 W

[1]

7. What is the carrier frequency in an AM wave when its highest frequency component is 850 Hz

and the bandwidth of the signal is 50Hz?

A. 80 Hz

B. 695 Hz

C. 625 Hz

D. 825 Hz

[1]

8. The functions of radio receiver are

A. Receive the Incoming modulated carrier by antenna

B. Select the wanted signal and reject the unwanted signals and noise

C. Detection and amplification of the information signal from the carrier

D. All of the above

[1]

9. Which one of the following statements concerning electromagnetic waves is false?

A. Electromagnetic waves carry energy.

B. X-rays have longer wavelengths than radio waves.

C. In vacuum, all electromagnetic waves travel at the same speed.

D. Lower frequency electromagnetic waves can be produced by oscillating circuits.

[1] 10. Coaxial cable offers a band width approximately MHz

A. 1

B. 20

C. 250

D. 1000

[1]


11. A radio station on the MW network transmits with a carrier frequency of 500 kHz, amplitude

modulated by an audio baseband of 100 Hz to 3.5 kHz.

(i) Sketch the frequency spectrum of the station [2]

(ii) calculate the bandwidth of the AM signal. [1]

12. Find matches/ Each Technology may be used only once

Electromagnetic Radiation Technology

X rays A TV broadcast signals

Microwaves B In a hospital to keep surgical equipment sterile

Gamma rays C Examining the inside of a weld in a steel oil pipe

Radio waves D Lamp used to warm a baby chick

Infrared waves E Measuring the speed of a passing car

Ultraviolet waves F Used by an oncologist (a physician who studies and

treats cancer)

Radar G Cell phone

[7]

13. If the statement is true, write “T” on the line in front of the statement. If it is false, write “F”

1)_________Electromagnetic radiation includes only visible light waves [1]

2) _________Microwaves are a type of infrared wave [1]

3) _____ Radio waves, microwaves and ultraviolet waves all have longer wavelengths than

visible light. [1]

4)_________Both X rays and gamma rays have higher frequencies than ultraviolet rays.

[1]

14. Describe sources of electromagnetic oscillations

_______________________________________________________________________ [2]

15. a) Describe the orbit of a geostationary satellite. [3]

16. Determine the frequency of a microwave 6.0 cm in length. (A microwave is an electromagnetic

wave. It travels through space at a speed of 3.0 x 108 m/s)

[2]

17. What is coaxial cable?

_________________________________________________________________________ [2]

Advantages_______________________________________________________________ [1]

Disadvantages_____________________________________________________________ [1]

18. What are the Advantages of digital transmission over analog?

[3]

19. In the original telephone system of 1876, every telephone was connected to every other

telephone by a pair of wires. Today the telephone is used worldwide as the result of the

invention of the exchange and the use of sampling using digital electronics.

Describe how each of these developments has meant that many telephone conversations

can take place at once.

..................................................................................................................................... [4]

20. In the modern telephone system, more and more coaxial cable has been replaced for long-

distance transmission of telephone signals by optic fibre.

State and explain two reasons for this change.

..................................................................................................................................... [4]

21. State and explain the effect on the transmitted analogue waveform of increasing, for the ADC

and the DAC, both the sampling frequency and the number of bits in each sample.

..................................................................................................................................... [3]

22. State a typical wavelength for communication between the Earth‟s surface and a geostationary

satellite. [1]

23. State one advantage and one disadvantage of the use of a geostationary satellite rather than a

satellite in polar orbit for telephone communication. [2]


24. The digital transmission of speech may be represented by the block diagram of Fig.1

(a) State the purpose of the parallel-to-serial converter.

..................................................................................................................................... [2]

(b) Part of the signal from the microphone is shown in Fig.2

The ADC (analogue-to-digital converter) samples the analogue signal at a frequency of 5.0 kHz.

Each sample from the ADC is a four-bit digital number where the smallest bit represents 1.0 mV.

The first sample is taken at time zero.

Use Fig.2 to determine the four-bit digital number produced by the ADC at times

(i) 0.4 ms, ............................................................................................................................. [1]

(ii) 0.8 ms. ............................................................................................................................. [1]

(c) The digital signal is transmitted and then converted to an analogue form by the DAC

(digital-to-analogue converter). Using data from Fig.2, draw, on the axes of Fig.3, the output

level of the transmitted analogue signal for time zero to time 1.2 ms.

[4]

Total: 60

Mark scheme

Task

Answer Mark Additional

information

1

2

3

4

5

6

7

8

9

10

B

D

D

A

B

C

D

D

B

B

1

1

1

1

1

1

1

1

1

1

11 (i)

(ii) Bandwidth = 503.5-497.5 = 7kHz

2

1

12 Electromagnetic Radiation Technology

C X rays A. TV broadcast signals

G Microwaves B In a hospital to keep surgical

equipment sterile

F Gamma rays C Examining the inside of a weld in

a steel oil pipe

A Radio waves D Lamp used to warm a baby chick

D Infrared waves E Measuring the speed of a passing

car

B Ultraviolet waves F Used by an oncologist (a physician

who studies and treats cancer)

E Radar G Cell phone

7

13 1) False

2) False

3) True

4) True

1

1

1

1

14 correctly describes sources of oscillation

gives examples

1

1

15

Orbits around the Earth‟s equator.

Takes one day for a complete orbit.

Stays over one point on the Earth OR height of orbit 36 000 km

above Earth‟s surface.

1

1

1

16 5*109

Hz 2

17 Single copper wire surrounded by at least three layers

Often used for cable television wiring

ADVANTAGES No cables needed/ Multiple channels available/

Wide bandwidth

Disadvantages Line-of-sight will be disrupted if any obstacle,

such as new buildings, are in the way

or

Signal absorption by the atmosphere. Microwaves suffer from

attenuation due to atmospheric conditions

or

Towers are expensive to build

1

1

1

1

18 1) Digital signals do not get corrupted by noise etc. You are sending

a series of numbers that represent the signal of interest (i.e. audio,

video etc.)

2) Digital signals typically use less bandwidth. This is just another

way to say you can cram more information (audio, video) into the

same space.

3) Digital can be encrypted so that only the intended receiver can

decode it (like pay per view video, secure telephone etc.)

1

1

1

19 a) The public switched telephone network connects every

telephone through exchanges.

Without exchanges too many telephones and interconnecting wires

are needed.

One cable can handle many telephone conversations at once.

Sampling places a series of digital bits from many telephone

conversations on one cable.

1

1

1

1

20 Any two reasons and explanation/Less attenuation so fewer

repeater/regeneration amplifiers needed.

More bandwidth so more data can be sent per second/

more telephone calls made at once.

Less interference/noise so fewer regeneration amplifiers needed.

Lower diameter/ weight so easier to handle/cheaper.

1

1

1

1

21 increasing number of bits reduces step height

increasing sampling frequency reduces step depth / width

reproduction of signal is more exact

1

1

1

22 First satellites used wavelengths of about 5 cm; typically now

between 1 mm and 1 cm.

1

23 Advantage: permanent link with ground station/dishes do not

have to be moved.

Disadvantage: greater time delay for signal OR further away so

signal weaker.

1

1

24 (a) takes all the simultaneous digits for one number

and „sends‟ them one after another (along the transmission line)

(b) (i) 0111

(ii) 0110

(c) levels shown

(–1 for each error or omission)

correct basic shape of graph i.e. series of steps

with levels staying constant during correct time intervals

(vertical lines in steps do not need to be shown

1

1

1

1

1

1

1

1

Total: 60




1. If a secondary coil has 40 turns, and, a primary coil with 20 turns is charged with 50 V of

potential difference, then potential difference in secondary coil would be

A. 50 V in secondary coil

B. 25 V in secondary coil

C. 60 V in secondary coil

D. 100 V in secondary coil

[1]

2. What is the peak value of a household appliance that uses a 230 V ac source?

A. 325 V

B. 163 V

C. 480 V

D. 230 V

[1]

3. In transformer, alternating current is induced in

A. primary coil

B. secondary coil

C. iron core

D. resistor

[1]

4. Why is ac current transfer more effective than dc current transfer over long distances?

A. due to step-up and step-down transformers reducing I-R losses

B. due to the use of ac generators

C. due to the height of power lines

D. due to very high voltages

[1]

5. A high-voltage powerline operates at 500 000 V-rms and carries an rms current of 500 A. If the

resistance of the cable is 0.050Ω/km, what is the resistive power loss in 200 km of the

powerline?

A. 250 kW

B. 500 kW

C. 1 Megawatt

D. 2.5 Megawatt

[1]

6. An alternating current (a.c.) supply is connected to a resistor through a rectifier as shown in the

diagram.

Which pattern will be viewed on the screen of an oscilloscope connected across the resistor?

[1]

7. The graph shows the variation with time of the alternating current in a resistor.

The resistor has a resistance of 2.0 .

What is the mean power?

A. 0

B. 1.0 W

C. 1.4 W

D. 2.0 W

[1]

8. An alternating voltage is rectified using a diode and a capacitor C. The output is not constant;

there is a small variation in the current I in the resistor R.

[1]

9. The number of turns on the transformers is as shown in the figure. What is the output voltage of

the transformers, in volts, if the input voltage of the transformers is 5 V?

A. 10

B. 15

C. 30

D. 35

[1]

10. In an ac circuit, a 0.025-H inductor is connected to a generator that has an rms voltage of 25 V

and operates at 50.0 Hz. What is the rms current through the inductor?

A. 0.62 A

B. 2.0 A

C. 3.2 A

D. 7.1 A

[1]


11. An alternating current is represented by the equation: I = 2 sin 50t

(a) What is the peak value of the current?

_____________________________________________________________________ [1]

(b) Calculate the frequency of the supply

____________________________________________________________________ [2]

12. An alternating current (ac) source is connected to a resistor to form a complete circuit. The

trace obtained on an oscilloscope connected across the resistor is shown in the diagram below.

The oscilloscope settings are:

Y gain 5.0 V per division

time base 2.0 ms per division

(i) Calculate the peak voltage of the ac source.

answer = ....................................... V [1]

(ii) Calculate the rms voltage

answer = ....................................... V [1]

13. Calculate the inductive reactance of a 3.00 mH inductor when 10.0 kHz AC voltages are

applied.

What is the rms current if the applied rms voltage is 120 V?

____________________________________________________________________ [3]

14. A student is asked to design a circuit by which a direct voltage of peak value 9.0 V is obtained

from a 240 V alternating supply.The student uses a transformer that may be considered to be

ideal and a bridge rectifier incorporating four ideal diodes. The partially completed circuit

diagram is shown in Fig.

(a) On Fig., draw symbols for the four diodes so as to produce the polarity across the load as

shown on the diagram.

[2]

(b) Calculate the ratio

ratio =

................................................ [3]

15. An electrician uses a transformer to step the 230 V r.m.s. mains voltage down to 115 V r.m.s.

The secondary coil has 500 turns and is connected to a resistor of 5000 .

(a) Calculate the number of turns on the primary coil. [1]

(b) Calculate the current in the secondary coil. [1]

(c) Calculate the current in the primary coil. Assume that the transformer is 100 % efficient. [1]

(d) The electrician connects cables to the secondary coil that break down when the p.d.

between the wire and earth is larger than 130 V. Explain whether the cables will break

down when the transformer is switched on. [2]

16. (i) On Fig, draw the symbol for a capacitor, connected into the circuit so as to provide

smoothing.

[1]

number of turns on the secondary coil

number of turns on the primary coil

(ii) State how the amount of smoothing may be increased. [1]

17. Transformer A produces a very high voltage to transmit the electrical energy through the

National Grid. Explain why electrical energy is transmitted at a very high voltage

[2]

18. A resistor of 200 Ω and a capacitor of 15.0 µF are connected in series to a 220 V, 50 Hz ac

source. Calculate the current in the circuit. [2]

19. Which component, the resistor or the capacitor, will drop more voltage in this circuit?

[1]

20. Calculate all voltages and currents in this circuit, as well as the total impedance [4]

21. An alternating voltage is applied across each of the components as shown below.

In each case, sketch a graph to show the current through and voltage across the component.

State the phase relationship for each component.

[6]

22. The output from the transformer is to be full-wave rectified. Fig. shows part of the rectifier

circuit.

On Fig, draw diode symbols to complete the diagram of the rectifier such that terminal A of the

resistor R is positive with respect to terminal B

[2]

23. Suggest one advantage of full-wave rectification as compared with half-wave rectification.

[1]


24. A sinusoidal alternating voltage supply is connected to a bridge rectifier consisting of four ideal

diodes. The output of the rectifier is connected to a resistor R and a capacitor C as shown in

Fig.1

The function of C is to provide some smoothing to the potential difference across R. The variation

with time t of the potential difference V across the resistor R is shown in Fig.2.

(a) Use Fig.2 to determine, for the alternating supply,

(i) the peak voltage,

peak voltage = ............................................. V [1]

(ii) the root-mean-square (r.m.s.) voltage,

r.m.s. voltage = ............................................. V [1]

(iii) the frequency. Show your working.

frequency = ........................................... Hz [3]

(b) (i) determine the change in potential difference [1]

(ii) determine the change in charge on each plate of the capacitor [2]

(iii) show that the average current in the resistor is 1.1 × 10–3

A [2]

(c) Use the graph and the value of the current given in (b)(iii) to estimate the resistance of

resistor R. [2]

Total: 60

Mark scheme

Task

Answer Mark Additional

information

1

2

3

4

5

6

7

8

9

10

D

A

B

A

D

C

D

D

C

C

1

1

1

1

1

1

1

1

1

1

11 a) 2A

b) 2f = 50; f = 25Hz;

1

2

12 10 V

7.1 V

1

1

13 I = V/XL

188 Ω

0.637 A

1

1

1

14 a) all four diodes correct to give output, regardless of polarity

connected for correct polarity

b) Ns / Np = Vs / V p

V0 = √2 Vrms

ratio = 9.0 / (√2 × 240)

= 1/38 or 1/37 or 0.027

1

1

1

1

1

15

a) Number of turns on the primary 230

115 500 1000 turns

b) Is R

Vs 5000

115= 0.023 A r.m.s.

c) Ip 0.023 1000

500= 0.0125 A 0.013 A r.m.s.

d) Peak voltage 115 2 162 V

so the cables will break down

1

1

1

1

1

16 (i) correct symbol, connected in parallel with R

(ii) larger capacitor / second capacitor in parallel with R (not

increase R)

1

1

17 To minimize losses for Joule heating

ohmic and resistive heating - process of heating up the conductor as

electric current flows through it.

1

1

18 Z= 291.5 Ω

0.755 A

1

1

19 The resistor will drop more voltage. 1

20 Ztotal = 6.944 kΩ

I = 4.896 mARMS

VL = 23.07 VRMS

VR = 24.97 VRMS

1

1

1

1

21

1

1

1

1

1

1

22

1

1

23 more (output) power available/ less ripple for same smoothing

capacitor/ any sensible suggestion

1

24 (a)

(i) peak voltage = 4.0V

(ii) (ii) r.m.s. voltage (= 4.0/√2) = 2.8V (iii) ii) period T = 20ms

frequency = 1 / (20 × 10–3

)

frequency = 50Hz

(b) (i) ΔV = 4.0 - 2.4 (see graph) = 1.6V

(ii) ΔQ = CΔV ΔQ = 8.0 x 10

-6 C

(iii) t = 7.0 x 10-3

s (see graph)

I = (8.0 x 10-6

)/(7.0 x 10-3

)

(c) Average voltage = 3.2V

R = 2900 Ω

1

1

1

1

1

1

1

1

1

1

1

1

Total: 60




1. A nucleus of magnesium decays into a nucleus of sodium by emitting a β+ particle. The decay is

represented by the equation shown.

𝑎

+

What are the values of P and Q?

P Q

A 22 11

B 22 13

C 23 11

D 23 13

[1]

2. What information did Millikan use to determine the charge on an electron? A. The rate at which the oil drop was rising from the plate.

B. The strength of the electric field.

C. The mass of the oil drop.

D. All of the above.

[1] 3. Alpha, beta and gamma radiations have various depths of penetration in matter and different

charges. Which row best summarises the penetration and charge of each radiation?

Alpha beta gamma

A absorbed by a sheet of card

negative charge

absorbed by several mm of

aluminium

no charge

not fully absorbed by several cm

of lead

no charge

B absorbed by a sheet of card

negative charge


aluminium

positive charge


of lead

no charge

C absorbed by a sheet of card

positive charge


aluminium

negative charge


of lead

no charge

D absorbed by several mm of

aluminium

positive charge

not fully absorbed by several

cm of lead

negative charge

absorbed by a sheet of card

no charge

[1]

4. Which change will not change the kinetic energy of the most energetic electrons emitted in the

photoelectric effect?

A. changing the brightness of the light

B. changing the frequency of the light

C. changing the metal the light is hitting

D. all of the above will change the electron‟s kinetic energy

[1]

5. If barium has a work function of 2.60 eV, what is its cutoff wavelength when used as a

phototube target? (h = 6.63 × 10−34

J⋅s, c = 3.00 × 108 m/s, 1 eV = 1.60 × 10

−19 J, and 1 nm =

10−9

m)

A. 398 nm

B. 478 nm

C. 497 nm

D. 596 nm

[1] 6. A particle is in a uniform field. The particle experiences a force in the opposite direction to the

field.

Which field is the particle in, and on which property of the particle is the field acting?

[1]

7. Two α-particles with equal energies are deflected by a large nucleus.

Which diagram best represents their paths?

[1]

8. When an electron falls from an orbit where n = 2 to n = 1:

A. a photon is emitted.

B. A photon is absorbed.

C. No change in atomic energy.

D. The atomic energy decreases to zero.

[1]

9. When an electron jumps from an orbit where n = 1 to n = 4, its energy in terms of the energy of

the ground level (E1) is:

A. E1/9

B. E1/16

C. 4 E1

D. 16 E1

[1]

10. What can be assumed to be the maximum range of an -particle in air?

A. a few millimetres

B. a few centimetres

C. a few metres

D. a few kilometres

[1]


11. This question is about nuclear binding energy.

The table below gives the mass defect per nucleon of deuterium and helium-4

Mass defect per nucleon / u

0.00120

0.00760

(a) Explain the term mass defect. [1]

(b) Calculate the energy, in joule, that is released when two deuterium nuclei fuse to

form a helium-4 nucleus.

[2]

12. (i) True or False: Maximum Kinetic Energy of emitted electrons is independent of frequency

and directly proportional to intensity of incident light

________________________[1]

(ii) True or False: Photons are electrically neutral and not deflected by electric or magnetic

fields

______________________[1]

(iii) True or False: In a photon-particle collision, photon may be absorbed in a collision or a

new one created.

______________________[1]

13. What is the difference of alpha beta and gamma radiation?

_____________________________________________________________________[3]

14. a) Define the half-life of a radioactive isotope. [1]

b) The half-life of a particular isotope is 20 minutes. A sample initially contains N0 nuclei

of this isotope. Determine the number of nuclei of the isotope left in the sample after:

i) 20 minutes [1]

ii) 1.0 hour. [2]

H21

.He42

H21

He42

15. The half-life of the radon isotope Rn22086 is 56 s.

a) Determine the decay constant in s−1

. [2]

b) Calculate the activity of a sample containing 6.0 1010

nuclei of Rn22086 . [2]

16. a) Distinguish between the random and the spontaneous nature of radioactive decay. [2]

b) In each case below, write a nuclear decay equation.

i) The polonium isotope Po21084 emits an α-particle and changes into an isotope of

lead (Pb). [1]

ii) The strontium isotope Sr9038 emits a β-particle and changes into an isotope of

yttrium (Y). [1]

17. White light is incident on a cloud of cool hydrogen gas, as illustrated in Figure

.

The spectrum of the light emerging from the gas cloud is found to contain a number of dark lines.

Explain why these dark lines occur. _______________________________________[3]

18. Some electron energy levels in a hydrogen atom are illustrated in Figure

One dark line is observed at a wavelength of 435 nm.

Calculate the energy, in eV, of a photon of light of wavelength 435 nm.

energy = ................................................... eV [ 2] 19. Complete the following nuclear reactions:

a. 88

226Ra ?? ? + 1

0e

b. 84

209Po 82205Pb + ?

? ?

[2]

20. An electron is accelerated from rest in a vacuum through a potential difference of 4.7 kV.

Calculate the de Broglie wavelength of the accelerated electron.

[2]

21. a) Write down Einstein‟s famous equation relating mass and energy. [1]

b) Determine the change in energy equivalent to a change in mass:

i) of 1.0 g [1]

ii) equal to that of an electron (9.1 10−31

kg). [1]

22. a) Explain why external energy is required to „split‟ a nucleus. [1]

b) Use the data given below to determine the binding energy and the binding energy per

nucleon of the nuclide U23592 (mass of proton 1.007 u mass of neutron 1.009 u mass of

uranium-235 nucleus 234.992 u)

[2]


23. (a) The following equation describes the release of electrons from a metal surface illuminated

by electromagnetic radiation.

hf = Φ + mv2

ma x/2

Explain briefly what you understand by each of the terms in the equation.

hf ................................................................................................................................[1]

k.e.max .........................................................................................................................[1]

Φ.....................................................................................................................[1]

(b) Calculate the momentum p of an electron travelling in a vacuum at 5% of the speed of light.

p = ..........................................................[2]

What is the de Broglie wavelength of electrons travelling at this speed?

λ = ..........................................................[2]

Why are electrons of this wavelength useful for studying the structure of molecules? [1]

24. (a) An experiment in which α-particles were deflected by a gold foil produced new insights

into the structure of the atom. Which conclusion can be drawn from the results of the

experiment?

[1]

(b) If there was air between the alpha source and the gold foil, the air would become

ionised. Explain what is meant by the term "ionised" [2]

(c) Describe the results of the experiment and explain clearly how he linked his results to

his conclusion [3]

Total: 60

Mark scheme

Tas

k

Answer Mar

k

Additiona

l

informati

on

1

2

3

4

5

6

7

8

9

10

C

B

C

A

B

A

A

A

D

B

1

1

1

1

1

1

1

1

1

1

11 (a) difference in mass between mass of nucleus;

and mass of (totally) separate nucleons;

(b) mass of helium-4 = 4 0.00760 = 0.0304 u

and mass of two deuteriums = 4 0.00120 = 0.0048u;

mass defect = 0.0256u;

energy = 0.0256 1.66 1027 (3 108)2; = 3.8 1012 J;

1

1

1

12 (i) False

(ii) True

(iii) True

1

1

1

13 Alpha radiation: corpuscular radiation, helium atoms

Beta radiation: electrons

Gamma radiation: electromagnetic radiation of high energy

1

1

1

14 a) The half-life of a radioactive isotope is the mean time taken for the

number of nuclei of the isotope to decrease to half the initial

number.

b) i) 20 minutes is 1 half-life, so number of nuclei left 2

0N

ii) 1.0 hour is 3 half-lives.

Number of nuclei left 82

1 00

3N

N

1

1

1

1

15

a) t1/2

693.0 so λ

1/2

693.0

t

λ 56

693.0

λ 1.238 102

s1

1.2 102

s1

b) A λN

1

1

1

A 56

693.0 6.0 10

10

A 7.4 108 Bq

1

16 random

• a particular nucleus can decay at any time/ count rate or

readings fluctuate/ no-one can predict when a nucleus will

decay

spontaneous

• each nucleus decays independently of any other

• each nucleus has the same chance of decaying as any other

• the decay of nuclei cannot be affected by external factors

i) Po21084 Pb He 206

8242

ii) Y e 9039

01

1

1

1

1

17 photon „absorbed‟ by electron

B1 photon has energy equal to difference in energy of two energy

levels electron de-excites emitting photon (of same energy) in any

direction

1

1

1

18 E = hc /λ

2.86 eV (2 s.f)

1

1

19 a) A=226, Z=89

b) He4

2

1

1

20 energy = p2 /2m or EK = ½mv2 and p = mv p=3.7 × 10

–23 N s

λ = h/p=1.8 × 10–11

m

1

1

21 a) change in energy change in mass (speed of light)2 or ΔE

Δmc2

b) ΔE 9.0 1013

J

c) ΔE 8.2 1014

J

1

1

1

22 (a) The nucleons within the nucleus are held tightly together by the

strong nuclear force.

(b) binding energy 3.219 1027

(3.0 108)2 2.897 10

10 J

binding energy per nucleon 235

10897.2 10 1.233 10

12 1.2

1012

J

1

1

1

23 (a) hf Energy of a photon

k.e.max Kinetic energy of emitted electron/equivalent

φ Energy to release electron from surface / equivalent

(b) p = mv

p = 1.37 × 10–23

N s/kg m s–1

λ = 4.84 × 10–11

m

λ</ similar to size/spacing atoms/molecules

1

1

1

2

2

1

no ecf for

incorrect

mass

Sr90

38

24 (a) Atomic nuclei occupy a very small fraction of the volume of an

atom

(b) Ionise describes the process where radiation knocks electrons out of

atoms turning the atoms into (positive) ion

(c) 1) Most of the alpha particles went straight through.

2) Some of the alpha particles were deflected/deviatedbecause the

nucleus was positively charged and repelled the positively charged alpha

particles.

3) A few of the alpha particles were repelled straight back/at large

angles

Because the mass of the atom was concentrated in the nucleus/the

nucleus is very dense (not “large or heavy”).

1

1

1

1

1

1

Total: 60

Collection of tasks for summative assessment ... - nis.edu.kz

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Transcript of Collection of tasks for summative assessment ... - nis.edu.kz