Post on 18-Oct-2015
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Question No. 1
which of the following methods can be used to charge a metal sphere positively without touching it . Select the best
Connect the positive terminal a battery and float the other end of the battery
Bring a negatively charged rod near the sphere and touch it to ground for a short while
Rub it with a piece of silk
Rub it with a piece of fur
Clear
If{\rm{1}}{0^{\rm{9}}}electrons move out of a body to another body every second, how much time is approximately required to get a total charge of 1 C on the other body?
200 years
120 years
180 years
220 years
Electric charge
is a property of protons only
is a property of particles such as atoms,ions,electrons etc that defines their behaviour in electrical fields.
is a property of neutrons onlz
is a property of electrons only
Clear
Electric charges are of
4 types
2 types
5 types
3 types
Conservation of charges in tribo electric charging
implies both are negatively charged
implies one is positively charged and the other is negatively charged.
implies half are positively charged and other half are neutral
implies both are positively charged
Clear
wo positive charges
always attract each other
repel each other
attract each other
attract each other at times and repel at other times
Clear
Charge is quantized means
charges can take on any continuous value
charges can take on discrete values that are multiples of charge on electron
charges can take on discrete values that are multiples of charge on neutron
charges can take on any discontinuous value
Clear
Ionization of a neutral atom is the
only gain of one or more neutrons
only gain of one or more electrons
only gain of one or more protons
gain or loss of one or more electrons
electrostatic force is
force exerted by an electron on a neutron
force exerted by one charge on another when the two are at rest in a given frame of reference
force exerted by one charge on another when the two are accelerating in a given frame of reference
force exerted by one charge on another when the two are moving in a given frame of reference
Clear
Conductors are materials
that allow only random movement of electrons
that allow movement of protons
that allow movement of electrons
that allow movement of neutrons
Clear
In charging by Induction
a metallic object is charged by bringing a charged object near it
a metallic object by touching touching with a charged object
a metallic object is charged by rubbing it with silk
a metallic object is charged by rubbing it with fur
Clear
For chargesq1andq2separated by a distance R the magnitude of the electrostatic force is given by
B .F=q1q240R
F=q1q240R3
F=q140R2
F=q1q240R2.
The unit of charge is
ampere
coulomb
ohm
volt
Electric field at a point is defined as
electric force experienced by a dipole at that point
electric force per unit charge experienced by a unit charge at that point
electric force experienced by a charge at that point
electric force experienced by two charges at that point
Clear
According to superposition of electric fields
The electric field of any combination of charges is the cross product of the individual fields.
The electric field of any combination of charges is the vector sum of the individual charges.
The electric field of any combination of charges is the vector sum of the fields caused by the individual charges.
The electric field of any combination of charges is the scalar sum of the fields caused by the individual charges.
Clear
Electric field lines can be said to be
lines of equal Electric field
graphical representation of electric fields.
drawing lines of electric fields
lines of equal Electric voltage
Clear
At any point on S on an electric field line
the perpendicular to the line is in the direction ofEat that point
the curvature is in the direction ofEat that point
the tangent to the line is in the direction ofEat that point
the binormal to the line is in the direction ofEat that point
Clear
An electric dipole is
a pair of electric charges of equal magnitude q but opposite sign, separated by a distance
a pair of electric charges of equal magnitude q but negative sign, separated by a distance d
a pair of electric charges of equal magnitude q but positive sign, separated by a distance d
a pair of electric charges of equal magnitude q separated by a distance d
Clear
The direction of an electric dipole
is perpendicular to line from positive to negative charge
is from negative to positive charge
is perpendicular to line from negative to positive charge
is from positive to negative charge
Clear
Electric flux
Is a measure of the electric power through a surface
Is a measure of the electric field potential through a surface
Is a measure of the area of electric field through a surface
Is a measure of the "flow" (in analogy with flow of fluids) of electric field through a surface.
ClearGauss's law states that
the total electric field flux coming out of a closed surface equals the net charge enclosed within the volume
the total electric field flux coming out of a closed surface equals the net charge enclosed within the volume divided by0
the total electric field flux coming out of an open surface equals the net charge enclosed within the volume divided by0
the total electric field flux coming out of a closed surface equals the charge enclosed within the volume divided by0
ClearAn electric dipole in an electric field experiences a torque {tex}\vec \tau {tex}
equal to the vector product of\vec E{tex} and{tex}\vec p
equal to the scalar product of\vec p{tex} and {tex}\vec E
equal to the scalar product of {tex}\vec E{tex} and{tex}\vec p{tex}
equal to the vector product of\vec p{tex} and {tex}\vec E
For a thin infinitely long straight wire of uniform linear charge densityat a distance R from the wire The magnitude ofE is
E=20R.
E=220R
B .E=40R
E=30R
For an Infinite thin plane sheet of uniform surface charge densitytexThemagnitudeoftexEis
A .E=20
E=220
E=203
E=0
For a thin spherical shell of uniform surface charge density, The magnitude ofEjust outside is
E=4R240r2
E=4R240r3
A .E=R240r2
E=4R240r2
Clear
An electric field can deflect
- rays
X rays
rays
Neutrons
Clear
Which one of the following graphs represents the variation of electric field strength E with distance r from the centre of a uniformly charged non conducting sphere?
Image B
Image C
Image D
Image A
Clear
A conducting sphere of radius 5 cm is charged to 15 {tex}\mu {tex} C. Another uncharged sphere of radius 10 cm is allowed to touch it for enough time. After the two are separated, the surface density of charge on the two spheres will be in the ratio
0.0840277777778
0.0423611111111
0.125694444444
0.0430555555556
Clear
A Gaussian sphere encloses an electric dipole within it. Total flux across the sphere is
dependent on position of the charge
double that due to single charge
half that due to a single charge
Zero
A cylinder of radius R and length L is placed in an uniform electric field E parallel to the cylinder axis. The total flux for the surface of the cylinder is given by
R2E
2R2E
R2+L2
C .0
When a negatively charged conductor is connected to earth,
Electrons flow from the conductor to the earth
Protons flow from the conductor to the earth
Electrons flow from the earth to the conductor
No charge flow occurs. Top of FormAn uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like
Correct option is B
Correct option is A
Correct option is C
Correct option is D
Clear
Bottom of FormAnswer SheetGeneral
1234
5678
9101112
131415
Submit TestPreviousA hollow spherical conductor of radius 2m carries a charge of 500C. Then electric field strength at its surface is
1.125106N/C.
4.5106N/C
2.25106N/C
Zero
ClearA tennis ball which has been covered with charges is suspended by a thread so that it hangs between two metal plates. One plate is earthed, while other is attracted to a high voltage generator. The ball
hangs without moving
is attracted to the high voltage plate and stays there
swings backward & forward hitting each plate in turn
is repelled by earthed plate and stays there.
Clear
A metallic solid sphere is placed in a uniform electric field. In the figure, which path will the lines of force follow?
3.0
1.0
4.0
2.0
Eight dipoles of charges of magnitude e are placed inside a cube. The total electric flux coming out of the cube will be
16eo
A .8eo
eo
Zero
A charge q is placed at the center of the line joining two equal charges Q. The system of the three charges will be in equilibrium if q is equal to
Q/2
Q/4
Q/5
Q/2
Four point chargesqA=2C,qB=5C,qC=2C,andqD=5Care located at the corners of a square ABCD of side 10 cm. Force on a charge of1Cplaced at the centre of the square is
1.8 N
4.5 N
3.6
0 N
A system has two chargesqA=2.5107CandqB=2.5107Clocated at points A: (0, 0, 15 cm) and B: (0,0, +15 cm), respectively. What are the total charge and electric dipole moment of the system?
zero,7.5108Cm
zero,6.5108Cm
zero,5.5108Cm
zero,8.5108Cm
An electric dipole with dipole moment4109Cm is aligned at30with the direction of a uniform electric field of magnitude5104NC1. Calculate the magnitude of the torque acting on the dipole.
3.5104Cm
1.0104Cm
1.5108Nm
2.5104Cm
Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is6.5107C? The radii of A and B are negligible compared to the distance of separation.
B2.5102N
3.5102N
1.5102N
4.5102N
Clear
Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm and have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B?
A3.7103/N
6.7103/N
5.7103/N
4.7103/N
Consider a uniform electric fieldE=3103N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a60angle with the x-axis?
40Nm2/C,25Nm2/C
40Nm2/C,15Nm2/C
30Nm2/C,15Nm2/C
A20Nm2/C,15Nm2/C
Clear
Careful measurement of the electric field at the surface of a black box indicates that the net outward flux through the surface of the box is8.0103Nm2/C. (a) What is the net charge inside the box? (b) If the net outward flux through the surface of the box were zero, could you conclude that there were no charges inside the box?
0.05C, No
0.07C, No
0.06C, Yes
A 0.04C, Yes
A point charge of 2.0Cis at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?
2.2105Nm2/C
2.1105Nm2/C
A1.7105Nm2/C
1.9105Nm2/C
Clear
point charge causes an electric flux of1.0103Nm2/Cto pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface? (b) What is the value of the point charge?
B103Nm2/C,8.8nC
103Nm2/C,6.8nC
103Nm2/C,7.8nC
103Nm2/C,8.8nC
A point charge + q is placed at the mid point of a cube of side L. The electric flux emerging from the cube is
qo
zero
q6L2o
qL2o
A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of80.0C/m2. (a) Find the charge on the sphere. (b) What is the total electric flux leaving the surface of the sphere?
1.35103C,1.6108Nm2/C
1.45103C,1.6108Nm2/C
1.55103C,1.6108Nm2/C
A1.25103C,1.2108Nm2/C
Clear
Gravitational force is the smallest between
two pens weighing 100gms at a distance of 0.4 m
earth and the sun
earth and the sun
two books of weight 1kg each at a distance of 1 m
Clear
A solid metallic sphere has a charge + 3Q. Concentric with this sphere is a conducting spherical shell having charge Q. The radius of the sphere is a and that of spherical shell is b (b>a). The electric field at a distance R(a