1. A test charge is moved from lower potential point to a higher potential point. The potential energy of test charge will ?

remain the same

decrease

become zero

increase

Answer: increase

Explanation:

A test charge is moved from a lower potential point to a higher potential point. The potential energy of the test charge will increase.


2. A conductor with a positive charge ?

is always at zero potential.

is always at +ve potential.

may be at +ve, zero or -ve potential.

is always at negative potential.

Answer: may be at +ve, zero or -ve potential.

Explanation:

May be at positive, zero or negative potential, it is according to the way one defines the zero potential.


3. In a region of constant potential ?

the electric field is zero

the electric field is uniform

the electric field shall necessarily change if a charge is placed outside the region

None of these

Answer: the electric field is zero

Explanation:

In a region of constant potential (V = constant) , E=-dVdr=0, i.e., electric field is zero. As E=0, there can be no charge inside the region.


4. When air in a capacitor is replaced by a medium of dielectric constant K, the capacity ?

remains constant

decreases K times

increases K times

increases K^2 times

Answer: increases K times

Explanation:

We know, capacity: C= kA/d Now when air is replaced by dielectric medium of constant k This implies that the capacitance increases K times


5. Two metal pieces having a potential difference of 800 V are 0.02 m apart horizontally. A particle of mass 1.96 × 10 kg is suspended in equilibrium between the plates. If e is the elementary charge, then charge on the particle is ?

6

3

0.1

8

Answer: 3

Explanation:

If the e is the elementary charge, then charge on the particle is n×1.6×10-19=1.96×10-15×9.8×0.02800?n=3.


6. The potential gradient at which the dielectric of a condenser just gets punctured is called ?

dielectric number

dielectric resistance

dielectric constant

dielectric strength

Answer: dielectric strength

Explanation:

The potential gradient at which the dielectric of a condenser just gets punctured is called dielectric strength.


7. In a parallel plate capacitor, the capacity increases if ?

dielectric constantly decreases.

area of the plate is increased.

distance between the plates increases.

area of the plate is decreased.

Answer: area of the plate is increased.

Explanation:

capacitance will increase with increase in Area.


8. The radii of two metallic spheres A and B are r1 and r2 respectively (r1 > r2). They are connected by a thin wire and the system is given a certain charge. The charge will be greater ?

zero on both.

on the surface of the sphere B.

on the surface of the sphere A.

equal on both.

Answer: on the surface of the sphere A.

Explanation:

After connection of wire, potential becomes equal, i.e, Q1/r1 = Q2/r2 or Q1/Q2 = r1/r2 when r1 > r2, then Q1 > Q2.


9. If a unit positive charge is taken from one point to another over an equipotential surface, then ?

no work is done.

work done is constant.

work is done by the charge.

work is done on the charge.

Answer: no work is done.

Explanation:


10. Equipotential surfaces ?

will be more crowded near sharp edges of a conductor.

are closer in regions of large electric fields compared to regions of lower electric fields.

will always be equally spaced.

both (a) and (b) are correct.

Answer: both (a) and (b) are correct.

Explanation: