SEKOLAH MENENGAH KEBANGSAAN RAWANG

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PHYSICS MODULE 11. A student carries out an experiment to study the relationship of the distance between two coherent sources of sound waves, a and the distance between two consecutive instances of loud sound, x. The distance between the loudspeakers and the location where the sound is detected, D is 4.0 m.

Figure 1 shows the arrangement of the apparatus for this experiment. The sound is detected with the help of a cathode ray oscilloscope (C.R.O.) Initially, a is fixed at a distance of 1.0 m. Figure 2 shows the scaled-down distance between two consecutive instances of loud sound, x.

The above procedure is repeated by varying the values of a, to be 1.5 m, 2.0 m, 2.5 m and 3.0 mFigures 3, 4, 5 and 6 show the scaled-down distance between two consecutive instance of loud sound, x. Each instance of loud sound is indicated by a dot.

(Scale: 1 cm represents 0.2 m)

(a)For the experiment described, identify;

(i)the manipulated variable, (ii)the responding variable, (iii) a fixed variable.(b) (i) Measure the value of x for each value of a. (ii) Tabulate your result for a and x.

(c) Plot a graph of x against a

(i) Choose the most suitable type of material to be used to make hot plate. Explain the suitability of your

choice.

(ii) Explain why the other three designs are not suitable

Answer:

CharacteristicReason

. density

Less .. so makes it very light and easy to carry

It has specific heat capacity

It will transfer much heat to the sizzling

is the suitable It is because it has , and

..

3 A woman intends to serve ice cream to her children on a hot afternoon. Figure 1 shows four different types of cups that are available for her to contain the ice cream. The physical properties of the cups are labelled on the base of the cup.

(i) Choose the most suitable type of cup to be used to contain the ice cream for her children. Explain the

suitability of your choice.

(ii) Explain why the other three designs are not suitable

Answer: CharacteristicReason

. mass

Makes it very light and easy for children to carry

It has specific heat capacity

It will not transfer much heat to the icecream

..conductor of heat

The ice cream will melt very

.. rate of thermal expansion

It will . In shape and size when it is

.

is the suitable cup It is because it has , .

, . And

..

4 A student went for an eye examination and was told that she needed to make a pair of spectacles with lenses of power -4.OD. Table 1 gives the data on the types of lenses available to the student. Type of lensFocal length, f (m)Refractive index, nMaterial

Convex

Concave0.25

0.40

0.671.49

1.52

1.67

1.73

Glass

Plastic

(i) Which type of lens is suitable? Give a reason for your answer.(ii) By doing the appropriate calculations, determine the focal length of the lens to be used for the

spectacles. (iii) What is the most suitable value for the refractive index of the lens? Explain your answer.

(iv) Name the suitable material for the lens. Explain the advantage of the material you have choosen

(v) Figure 1 gives five types of lenses. Choose the most suitable lens to be used by the student. Justify your choice.

Answer:(i) A ..lens is suitable. It has power.(ii) Power = 1 , f = F

(iii) . Is most suitable retractive index. The lens can bend light .and the lens will

not too

(iv) .. is suitable material. It is light and not breakable.

(v) .is suitable lens. It is ., , . And ..

5 A girl wants to make a sprayer to water her plant by blowing into a tube attached to a container of water as shown in Figure 1 Figure 2 shows some possible designs for making the tube and container of the sprayer. You are asked to help her to design the sprayer.

(i) Choose the most suitable design for the tube from one of the three designs P, Q and R in Figure 2 and

explain the suitability of the design.

(ii) Explain why the other two designs are not suitable.(iii) Choose the most suitable design for the container from one of the three designs X, Y and Z in Figure 2

and explain the suitability of the design.

(iv) Explain why the other two designs are not suitable.

(v) By combining the tube and the container, explain how the sprayer works. [10 marks]

Answer:(i) Design is most suitable.

-This tube will produce a .. stream of air at the end of the tube because the crosssectional

area of the tube becomes smaller.(ii) Design . is not efficient because the cross-sectional area increases and the speed of air decreases. Design . will not produce a stream of air because its end is closed.

(iii) Design . is most suitable. (iv) Due to the hole in the stopper, the . of air in the container is the same as the pressure

. the container (or atmospheric pressure)

(a) Inference: . can influence (b)Hypothesis: The increase of , the .of compression

(c) Aim : To determine relationship between . And

.(d)Apparatus:

(e) Apparatus set-up:

(f) Procedure :

(g) Result:

(h) Data analyse:

(i) Conclusion:

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