Assertion and Reason Questions Chapter-2
Electrostatic
Potential and Capacitance
Assertion (A) and other labelled Reason (R). Select the correct answer to these
questions from the options as given below.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
1. Assertion (A): The electrostatic potential at any point on the equatorial
plane of an electric dipole is zero.
Reason (R): The potential due to equal and opposite charges of the
dipole cancels out at every point on the equatorial plane.
2. Assertion (A): The electric potential at a point midway between two like
charges is not zero.
Reason (R): The potentials due to two like charges at the midpoint
add up.
3. Assertion (A): The work done in moving a charge in an electrostatic field
from one point to another depends only on the initial and final positions.
Reason (R): The electrostatic force is a conservative force.
4. Assertion (A): A charged particle can move on an equipotential surface
without any work being done.
Reason (R): The electric field is always perpendicular to the
equipotential surface.
5. Assertion (A): The electric potential due to a point charge decreases as the
distance from the charge increases.
Reason (R): The electric potential is inversely proportional to
the distance from the charge.
6. Assertion (A): Two equipotential surfaces can never intersect.
Reason (R): At the point of intersection, the electric field would
have two different directions, which is not possible.
7. Assertion (A): The potential inside a hollow charged conductor is constant.
Reason (R): The electric field inside a hollow charged conductor
is zero.
8. Assertion (A): The electric potential at a point due to a dipole is zero if
the point is on the equatorial line.
Reason (R): The potentials due to the positive and negative
charges of the dipole cancel each other on the equatorial line.
9. Assertion (A): The potential due to a uniformly charged spherical shell is
zero at its center.
Reason (R): The electric field inside a uniformly charged
spherical shell is zero.
10. Assertion (A): The capacitance of a parallel plate capacitor increases if a
dielectric material is inserted between the plates.
Reason (R): A dielectric material reduces the electric field
between the plates of the capacitor.
11. Assertion (A): The potential energy of a system of two opposite charges is
negative.
Reason (R): The potential energy of the system is proportional to
the product of the charges.
12. Assertion (A): The electrostatic potential energy of a system of two like
charges increases as the distance between them decreases.
Reason (R): Like charges repel each other, and work is done to
bring them closer.
13. Assertion (A): The work done in moving a charge between two points on an
equipotential surface is zero.
Reason (R): The potential difference between two points on an
equipotential surface is zero.
14. Assertion (A): The electrostatic potential is constant throughout the
interior of a conductor in electrostatic equilibrium.
Reason (R): The electric field inside a conductor is zero in
electrostatic equilibrium.
15. Assertion (A): The electric potential of a charged spherical conductor is
the same at all points on its surface.
Reason (R): The electric field inside a spherical conductor is
zero.
16. Assertion (A): The capacitance of a capacitor depends on the geometry of the
plates and the dielectric medium between them.
Reason (R): Capacitance is a function of the charge and potential
difference between the plates.
17. Assertion (A): The potential inside a conductor in electrostatic equilibrium
is the same as the potential on its surface.
Reason (R): The electric field inside a conductor in electrostatic
equilibrium is zero.
18. Assertion (A): The energy stored in a capacitor is directly proportional to
the square of the charge on the plates.
Reason (R): The energy stored in a capacitor is given by
\(\frac{1}{2} \frac{Q^2}{C}\).
19. Assertion (A): The potential energy of a charged capacitor increases if the
charge on the plates increases.
Reason (R): The potential energy of a capacitor is proportional to
the square of the charge on its plates.
20. Assertion (A): A capacitor stores energy by storing charge on its plates.
Reason (R): The energy stored in a capacitor is given by
\(\frac{1}{2}\) QV .
21. Assertion (A): The potential at infinity is defined to be zero in
electrostatics.
Reason (R): This is done for mathematical convenience and
consistency in calculations.
22. Assertion (A): A capacitor can store energy even when it is not connected to
a battery.
Reason (R): A charged capacitor retains its charge indefinitely in
ideal conditions.
23. Assertion (A): The capacitance of a capacitor increases if the distance
between the plates decreases.
Reason (R): The capacitance is inversely proportional to the
distance between the plates.
24. Assertion (A): The potential difference across a capacitor is directly
proportional to the charge on its plates.
Reason (R): This relationship is given by the equation Q=CV.
25. Assertion (A): A capacitor with a dielectric has a higher capacitance than
the same capacitor without a dielectric.
Reason (R): The dielectric reduces the electric field between the
plates, allowing more charge to be stored.
26. Assertion (A): The potential energy of a capacitor is maximum when it is
fully charged.
Reason (R): At maximum charge, the voltage across the capacitor is
at its peak value.
27. Assertion (A): The capacitance of a parallel plate capacitor can be
increased by increasing the area of the plates.
Reason (R): Capacitance is directly proportional to the plate
area.
28. Assertion (A): The energy density in an electric field is directly
proportional to the square of the electric field strength.
Reason (R): The formula for energy density is given by
\(\frac{1}{2} εE^{2}\).
29. Assertion (A): A capacitor will discharge faster if it is connected to a
resistor with a lower resistance.
Reason (R): Lower resistance allows a higher current to flow,
resulting in a quicker discharge.
30. Assertion (A): The electric field inside a conductor in electrostatic
equilibrium is zero.
Reason (R): This is because the charges reside on the surface of
the conductor.
31. Assertion (A): The potential difference across a capacitor is independent of
the dielectric material used.
Reason (R): The potential difference depends only on the charge
and capacitance.
32. Assertion (A): When a dielectric material is inserted into a capacitor, the
charge on the plates increases.
Reason (R): The dielectric increases the capacitance of the
capacitor.
33. Assertion (A): The energy stored in a capacitor is released when it
discharges.
Reason (R): The discharge of a capacitor converts electrical
energy into other forms of energy.
34. Assertion (A): The electric potential due to a positive charge is positive.
Reason (R): The electric potential is defined as the work done in
bringing a unit positive charge from infinity to that point.
35. Assertion (A): Capacitors in series have the same charge on each capacitor.
Reason (R): The charge on capacitors in series is the same because
the current through each capacitor is the same.
36. Assertion (A): The total capacitance of capacitors in series is less than
the smallest capacitance in the series.
Reason (R): The formula for total capacitance in series results in
a smaller value than any individual capacitance.
37. Assertion (A): The total capacitance of capacitors in parallel is equal to
the sum of the individual capacitances.
Reason (R): In parallel, each capacitor experiences the same
potential difference, allowing the total charge to be additive.
38. Assertion (A): If the distance between the plates of a capacitor is doubled,
the capacitance is halved.
Reason (R): Capacitance is inversely proportional to the distance
between the plates.
39. Assertion (A): A capacitor can be charged to a higher voltage than its rated
voltage without any damage.
Reason (R): Exceeding the rated voltage can lead to breakdown of
the dielectric material.
40. Assertion (A): A charged capacitor behaves like a battery when it
discharges.
Reason (R): The capacitor provides a steady voltage until it is
fully discharged.
41. Assertion (A): The capacitance of a capacitor depends on the geometry of its
plates.
Reason (R): The area of the plates and the distance between them
affect the capacitance value.
42. Assertion (A): The potential energy stored in a capacitor can be expressed
in terms of charge and capacitance.
Reason (R): The energy can be given by U=\(\frac{1}{2}
QV\) and U=\(\frac{1}{2} CV^{2}\).
43. Assertion (A): The electric field between the plates of a capacitor is
uniform.
Reason (R): This uniformity is due to the parallel nature of the
plates.
44. Assertion (A): The energy stored in a capacitor is independent of the
dielectric constant of the material used.
Reason (R): The dielectric constant affects capacitance, which in
turn affects the energy stored.
45. Assertion (A): Capacitors are used in electronic circuits to smooth out
voltage fluctuations.
Reason (R): Capacitors can release energy quickly, which
stabilizes voltage.
46. Assertion (A): The dielectric strength of a material determines its
effectiveness as a dielectric in a capacitor.
Reason (R): Higher dielectric strength allows a capacitor to
operate at higher voltages without breakdown.
47. Assertion (A): A capacitor acts as an open circuit after being fully
discharged.
Reason (R): There is no charge stored on its plates in a fully
discharged state.
48. Assertion (A): The total charge in a closed circuit with capacitors is
conserved.
Reason (R): Capacitors can only store charge but cannot create it.
49. Assertion (A): The breakdown of a dielectric occurs at a certain critical
electric field strength.
Reason (R): When the electric field exceeds the dielectric
strength, it leads to ionization of the dielectric material.
50. Assertion (A): Increasing the temperature of a dielectric material generally
decreases its capacitance.
Reason (R): Increased temperature reduces the dielectric constant
of the material.