1.
If a unit positive charge is taken from one point to another over an equipotential surface, then
(a) work is done on the charge.
(b) work is done by the charge.
(c) work done is constant.
(d) no work is done.
2. A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The
potential at the centre of the sphere is
(a) 0 V
(b) 10 V
(c) Same as at point 5 cm away from the surface
(d) Same as at point 25 cm away from the surface
3. Which of the following options is correct? In a region of constant potential [NCERT Exemplar]
(a) the electric field is uniform.
(b) the electric field is zero.
(c) there can be charge inside the regiofi.
(d) the electric field shall necessarily change if a charge is placed outside the region.
4. 1 volt is equivalent to
5. Which of the following statement is true?
(a) Electrostatic force is a conservative force.
(b) Potential at a point is the work done per unit charge in bringing a charge from any point to
infinity.
(c) Electrostatic force is non-conservative
(d) Potential is the product of charge and work.
6. The work done in bringing a unit positive charge from infinite distance to a point at distance x
from a positive charge Q is W. Then the potential at that point is
7. In a region of constant potential
(a) the electric field is uniform.
(b) the electric field is zero.
(c) there can be no charge inside the region.
(d) both (b) and (c) are correct.
8. A test charge is moved from lower potential point to a higher potential point. The potential
energy of test charge will
(a) remain the same (b) increase
(c) decrease (d) become zero
9. An electric dipole of moment is placed in a uniform electric field . Then
(i) the torque on the dipole is
(ii) the potential energy of the system is
(iii) the resultant force on the dipole is zero. Choose the correct option.
(a) (i), (ii) and (iii) are correct
(b) (i) and (iii) are correct and (ii) is wrong
(c) only (i) is correct
(d) (i) and (ii) are correct and (iii) is wrong
10. Dielectric constant for a metal is
(a) zero (b) infinite (c) 1 (d) 10
11. When air is replaced by a dielectric medium of constant K, the maximum force of attraction
between two charges separated by a distance
(a) increases K times (b) remains unchanged
(c) decreases K times (d) increases K-1 times
12. In a parallel plate capacitor, the capacity increases if
(a) area of the plate is decreased.
(b) distance between the plates increases.
(c) area of the plate is increased.
(d) dielectric constantly decreases.
13. Ten capacitors, each of capacitance 1 μF, are connected in parallel to a source of 100 V. The
total energy stored in the system is equal to :
(A) 10-2 J (B) 10-3 J (C) 0·5 × 10-3 J (D) 5·0 × 10-2 J
14 . The capacitors, each of 4 μF are to be connected in such a way that the effective capacitance of
the combination is 6 μF. This can be achieved by connecting
(a) All three in parallel
(b) All three in series
(c) Two of them connected in series and the combination in parallel to the third.
(d) Two of them connected in parallel and the combination in series to the third.
15. The formula for electrostatic potential is _____________.
a. Electrostatic potential = Work done*charge
b. Electrostatic potential = Work done/charge
c. Electrostatic potential = Work done+charge
d. Electrostatic potential = Work done-charge
Numericals
1. A regular hexagon of side 10 cm has a charge 5 μC at each of its vertices. Calculate the potential at the centre of the hexagon.
2. A 12pF capacitor is connected to a 50V battery. How much electrostatic energy is stored in the capacitor?
3. Three capacitors of capacitances 2 pF, 3 pF and 4 pF are connected in parallel.
(a) What is the total capacitance of the combination?
(b) Determine the charge on each capacitor if the combination is connected to a 100 V supply.
