List of top Physics Questions on Capacitance

A parallel plate capacitor was made with two rectangular plates, each with a length of \( l = 3 \, {cm} \) and breadth of \( b = 1 \, {cm} \). The distance between the plates is \( d = 3 \, \mu{m} \). Out of the following, which are the ways to increase the capacitance by a factor of 10?
  • A. l = 30 cm, b = 1 cm, d = 1 μm
  • B. l = 3 cm, b = 1 cm, d = 30 μm
  • C. l = 6 cm, b = 5 cm, d = 3 μm
  • D. l = 1 cm, b = 1 cm, d = 10 μm
  • E. l = 5 cm, b = 2 cm, d = 1 μm
Consider a parallel plate capacitor of area \( A \) (of each plate) and separation \( d \) between the plates. If \( E \) is the electric field and \( \epsilon_0 \) is the permittivity of free space between the plates, then the potential energy stored in the capacitor is:
A parallel plate capacitor is charged by an ac source. Show that the sum of conduction current (\( I_c \)) and the displacement current (\( I_d \)) has the same value at all points of the circuit.
In the given circuit, the internal resistance of the cell is zero. If \( i_1 \) and \( i_2 \) are the readings of the ammeter when the key (K) is opened and closed respectively, then \( i_1 : i_2 = \)
internal resistance of the cell is zero
A capacitor of capacitance 2 μF is charged with the help of a 60 V battery. After disconnecting the battery, if this capacitor is connected in parallel with another uncharged capacitor of capacitance 1 μF, then the potential difference across the plates of the 2 μF capacitor is
The capacitance of a spherical capacitor is \( 100 \) pF. If the spacing between the two spheres is \( 1 \) cm, then the radius of the inner sphere of the capacitor is:
As shown in the figure, the work done to move the charge 'Q' from point C to point D along the semi-circle CRD is
work done to move the charge ’Q’ from point C to point D
The capacitance of a spherical capacitor is \( 100 \) pF. If the spacing between the two spheres is \( 1 \) cm, then the radius of the inner sphere of the capacitor is:
As shown in the figure, the work done to move the charge 'Q' from point C to point D along the semi-circle CRD is
work done to move the charge ’Q’ from point C to point D
If 27 charged water droplets, each of radius $10^{-6~\text{m}$ and charge $10^{-12}~\text{C}$ coalesce to form a single spherical drop, then the potential of the big drop is}
A capacitor of capacitance 2\(\mu\)F is charged to 50 V and then disconnected from the source. Later the gap between the plates of the capacitor is filled with a dielectric material. If the energy stored in the capacitor is decreased by 25% of its initial value, then the dielectric constant of the dielectric material is
A parallel plate capacitor of capacitance 1 μF is charged to a potential difference of 20 V. The distance between plates is 1 μm. The energy density between the plates of the capacitor is:
A galvanometer (G) of $2 \, \Omega$ resistance is connected in the given circuit. The ratio of charge stored in $C_1$ and $C_2$ is:
Circuit diagram
In an electrical circuit drawn below, the amount of charge stored in the capacitor is ______ $\mu C$.
electrical circuit
A capacitor of capacitance \( C \) and potential \( V \) has energy \( E \). It is connected to another capacitor of capacitance \( 2C \) and potential \( 2V \). Then the loss of energy is \( \frac{x}{3} E \), where \( x \) is \( \_\_\_\_ \).
A capacitor is made of a flat plate of area A and a second plate having a stair-like structure as shown in figure. If the area of each stair is \(\frac{A}{3}\) and the height is d, the capacitance of the arrangement is:
Problem Fig
When a parallel plate capacitor is charged up to 95 V, its capacitance is \( C \). If a dielectric slab of thickness 2 mm is inserted between plates and the plate separation is increased by 1.6 mm such that the potential difference remains constant, find the dielectric constant of the material:
Eight capacitors each of capacity \( 2 \) µF are arranged as shown in the figure. The effective capacitance between A and B is:
Eight capacitors each of capacity
The space between the plates of a parallel plate capacitor is halved and a dielectric medium of relative permittivity \( 10 \) is introduced between the plates. The ratio of the final and initial capacitances of the capacitor is:
Which of the following statements about dielectrics is correct?
When a dielectric slab is inserted between the plates of an isolated charged capacitor, the energy stored in it:
A capacitor of capacitance 5$\mu$F is charged by a battery of emf 10V. At an instant of time, the potential difference across the capacitors is 4V and the time rate of change of potential difference across the capacitor is 0.6 V/s. Then the time rate at which energy is stored in the capacitor at the instant is
The net charge on a charged capacitor is

Four metal plates, each with surfa area $A$ on one side, are plad with separation $d$ as shown in the figure. The capacitan between a and b is ($\varepsilon_0$ -- permittivity of free spa)

Between the plates of a parallel plate capacitor of plate area A and capacity 0.025 \( \mu \)F, a metal plate of area A and thickness equal to \( \frac{1}{3} \) of the separation between the plates of the capacitor is introduced. If the capacitor is charged to 100 V, then the amount of work done to remove the metal plate from the capacitor is