Class 12 Electrostatic Potential And Capacitance CBSE Questions & Answers

Class 12 · Electrostatic Potential And Capacitance

This is Physics Class 12 Electrostatic Potential and Capacitance CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

The capacity of a pure capacitor is 1 farad. In DC circuit its effective resistance will be

A
infinite
Correct
B
\({1 \over 2}r\)
C
1 \(\Omega \)
D
zero

A metal plate of thickness half the separation between the capacitor plates of capacitance C, is inserted between the plates. The new capacitance is

A
2C
Correct
B
0.0
C
\({c \over 2}\)
D
C

The amount of energy a capacitor can store is called its

A
reactance
B
Inductance
C
resistance
D
Capacitance
Correct

A variable capacitor and an electroscope are connected in parallel to a battery. The reading of the electroscope would be decreased by

A
Placing a dielectric between the plates
B
Decreasing the battery potential
Correct
C
Decreasing the distance between the plates
D
Increasing the area of overlapping of the plates

For a charged conductor of arbitrary shape, inside the conductor

A
E and V are zero
B
E is non-uniform but V is zero everywhere.
C
V= 0 and \({\rm{E}} \ne {\rm{0}}\)
D
E=0, but V is same as on the surface and non-zero
Correct

To make a condenser of 16 \(\mu {\rm{F}}\), 1000 volts, how many condensers are needed which have written on them “8 \(\mu {\rm{F}}\),, 250 volts”?

A
40.0
B
8.0
C
2.0
D
32.0
Correct

When 2 charged conductors are connected by a wire,

A
there is always loss of energy
Correct
B
there is always gain of energy
C
there is loss or gain of energy depending upon the potentials of the
D
there will not be any change in energy

In series combination of capacitors, potential drops across the individual capacitors are equal to

A
direct ratio of charges stored
B
inverse ratio of capacitors
Correct
C
direct ratio of capacitors
D
inverse ratio of charges stored.

An electrolytic capacitor is marked 8 \(\mu {\rm{F}}\), 220 V. It can be used in a circuit where the p.d. across the capacitor may be

A
300 V
B
200 V
Correct
C
500 V
D
1000 V

The action of the dielectric to increase the capacitance is due to

A
electric polarization
Correct
B
neutralization of charges
C
dipole orienting parallel to the plates.
D
movement of charges to the sides of dielectric

In electrolytic capacitors positive terminal is

A
one on which aluminium oxide film is formed
Correct
B
one on which aluminium oxide film is not formed
C
none of the above.
D
either of the two terminals

Submarine cables act as

A
parallel plate capacitor
B
cylindrical capacitor with outer cylinder earthed
Correct
C
spherical capacitor
D
cylindrical capacitor with inner cylinder earthed.

Dielectric polarization is the phenomenon

A
in which atomic dipoles are aligned in the direction of electric field and
Correct
B
In which atomic dipoles are aligned opposite to the direction of electric
C
In which atomic dipoles are aligned opposite to the direction of the electric
D
In which atomic dipoles are aligned in the direction of electric field and

When a capacitor is connected to a battery

A
a current flows in the circuit for sometime and then decreases to zero
Correct
B
the current keeps on increasing, reaching a maximum value when the
C
no current flows in the circuit at all
D
an alternating current flows in the circuit.

A parallel plate capacitor is charged and the charging battery is then disconnected. If the plates of the capacitor are moved farther apart by means of insulating handles

A
the charge on the capacitor increases
B
the capacitance increases
C
the electrostatic energy stored in the capacitor increases.
Correct
D
the voltage across the plates decreases