Test: Electrostatic Potential & Capacitance - NEET MCQ

# Test: Electrostatic Potential & Capacitance - NEET MCQ

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## 25 Questions MCQ Test Physics Class 12 - Test: Electrostatic Potential & Capacitance

Test: Electrostatic Potential & Capacitance for NEET 2024 is part of Physics Class 12 preparation. The Test: Electrostatic Potential & Capacitance questions and answers have been prepared according to the NEET exam syllabus.The Test: Electrostatic Potential & Capacitance MCQs are made for NEET 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Electrostatic Potential & Capacitance below.
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Test: Electrostatic Potential & Capacitance - Question 1

### For a charged conductor of arbitrary shape, inside the conductor

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 1

The potential difference between any two points inside the hollow conductor is zero. This means that the potential at all points inside the hollow charged conductor is the same and it is equal to the value of the potential at its surface.

The electric field on the surface of a hollow conductor is maximum and it drops to zero abruptly inside the conductor.

E = - dV/dr

Test: Electrostatic Potential & Capacitance - Question 2

### An equipotential surface is a surface ______.

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 2

When the potential at all points on the surface is the same, such a surface is called an equipotential surface.

The potential difference between any two points on an equipotential surface is zero.

Test: Electrostatic Potential & Capacitance - Question 3

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

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 3

An electroscope is a device that measures the potential difference.
If it is connected in parallel to the capacitor, the potential across it will be equal to the potential across the capacitor, which is equal to the potential across the battery.
On decreasing the battery potential, the potential difference across the electroscope reduces, and hence the reading reduces.

Test: Electrostatic Potential & Capacitance - Question 4

A 2μF capacitor C1 is charged to a voltage 100 V and a 4 μF capacitor C2 is charged to a voltage 50 V. The capacitors are then connected in parallel. What is the loss of energy due to parallel connection?

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 4

Test: Electrostatic Potential & Capacitance - Question 5

If the potential difference between the plates of a capacitor is increased by 0.1%, the energy stored in the capacitor increases by nearly:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 5

The intial energy stored in the capacitor C of potential difference V is
E = (1/2) CV2
When the p.d increased by ΔV, the energy stored will be ΔE.

Test: Electrostatic Potential & Capacitance - Question 6

If the diameter of earth is 128 x 10km, then its capacitance will be:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 6

The capacitance of a spherical conductor of radius R is

Test: Electrostatic Potential & Capacitance - Question 7

If a charge moves in an electrical field:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 7

When a charged particle moves in an electric field, its electric potential energy decreases, its kinetic energy will increase i.e. the total energy is conserved.

Test: Electrostatic Potential & Capacitance - Question 8

If the charge on a capacitor is increased by 2 coulomb, the energy stored in it increases by 21%. The original charge on the capacitor (in coulomb) is:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 8

The initial energy of the capacitor of capacitance C and charge Q1

When the charge increases to Q2 the change in the energy of the capacitor,

Given percentage increase of energy,

Since, Q2 - Q1 = 2
⇒ Q1 = 20 C

Test: Electrostatic Potential & Capacitance - Question 9

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

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 9

When capacitors are connected in series, they have equal charge but the potential difference across them is given by

Test: Electrostatic Potential & Capacitance - Question 10

A capacitor of capacitance C is fully charged by a 200 V supply. It is then discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat 2.5×102Jkg−1K−1 and of mass 0.1 kg. If the temperature of the block rises by 0.4 K, what is the value of C?

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 10

Energy stored in the capacitor
This is released as heat when the capacitor discharges through the metal block. The quantity of heat = mass xs p.heatx rise in temperature.
Q = m x s x Δθ = 0.1 x 2.5 x 102 x 0.4 = 10 J
U = Q; 2 x 104 C = 10; C = 5 x 10-4 F = 500 μF

Test: Electrostatic Potential & Capacitance - Question 11

64 water drops having equal charges combine to form one bigger drop. The capacitance of the bigger drop, as compared to that of smaller drop will be:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 11

Capacitance of the small drop of radius r C8 = 4πε0r  and that of the big drop of radius R is CB = 4πε0R .
The volume of 64 small drops,
The ratio

Test: Electrostatic Potential & Capacitance - Question 12

An electrolytic capacitor is marked 8 μF, 220 V. It can be used in a circuit where the p.d. across the capacitor may be:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 12

The breakdown of the potential of the capacitor is 220 V.

In order to prevent damage to a capacitor, it should be always used in a circuit where the p.d is less than its breakdown potential. The p.d difference can only be 200 V.

Test: Electrostatic Potential & Capacitance - Question 13

The capacitance of a parallel plate capacitor is 5 μF. When a glass slab of thickness equal to the separation between the plates is introduced between the plates, the potential difference reduces to 1/8 of the original value. The dielectric constant of glass is

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 13

When a dielectric of constant K is introduced between the plates of a capacitor, the potential V reduces to V/K. Therefore K=8

Test: Electrostatic Potential & Capacitance - Question 14

For a parallel plate capacitor ______________ possible potential difference between the capacitor plates.

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 14

When a dielectric is introduced between two charged plates of a capacitor having a charge Q and maintained at a potential difference of V, a reverse electric field is set up inside the dielectric due to dielectric polarization. This reduces the electric field in between the plates. The potential is also reduced.

Maximum potential is dependent on the charge on the plates. As the charge remains constant, the presence of the dielectric decreases the maximum potential between the plates.

Test: Electrostatic Potential & Capacitance - Question 15

Which of the following is true about equipotential lines?

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 15

Electric field lines show the direction of the electric field at the point. If the electric field lines were tangential, parallel, or opposite to the equipotential surface, a tangential field will exist on the surface and work done in moving a charge on the surface is not zero.

Therefore electric field lines are always perpendicular to the equipotential surface.

Test: Electrostatic Potential & Capacitance - Question 16

In electrolytic capacitors positive terminal is ________

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 16

Aluminium electrolytic capacitors have the Aluminium foil anode (positive terminal) which is attached and covered with a layer of Aluminium Oxide which acts as a dielectric. The whole assembly is covered using a paper separator soaked in electrolyte such as, Borax or Glycol and covered by Aluminium foil which acts as cathode ( negative electrode)

Test: Electrostatic Potential & Capacitance - Question 17

If a positive charge moves opposite to the direction of the electric field :

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 17

A positive charge experiences a force in the direction of the field.
If it moves opposite to the direction of the field, negative work is done by the electric field on the charge.
Potential energy of the charge increases since an external source is required to do work on the charge against the direction of the field, and the work done is stored in the charge as its potential energy.

Test: Electrostatic Potential & Capacitance - Question 18

Submarine cables act as __________

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 18

A submarine cable consists of an inner conductor which carries power. This conductor is covered by an insulator, which acts as a dielectric. The dielectric material is covered by a metal coating called shield, which is connected to ground.
The cable acts as a cylindrical capacitor, with the conductor acting as the inner cylinder, and the metal shield as the outer cylinder which is connected to earth.

Test: Electrostatic Potential & Capacitance - Question 19

When 2 charged conductors are connected by a wire,

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 19

Let the two conductors have capacitances C1 and C2 and let their potentials be V1 and V2 .
Total initial energy of the conductors,  U= (1/2)C1V12 + (1/2)C2V22
When two charged conductors are connected by a wire, the flow of charge stops when the potentials are equalized.
Let V be the common potential and Q1 and Q2 be the charges on the conductors after the common potential is attained.

The final energy

Therefore,

Test: Electrostatic Potential & Capacitance - Question 20

Electrostatic shielding is based on the _______

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 20

The electric field inside a cavity is always zero. The potential inside a cavity of a conductor is constant.
The potential difference between any two points inside a charged conductor is zero. This phenomenon is called electrostatic shielding.

Test: Electrostatic Potential & Capacitance - Question 21

Two metallic spheres of radii 1 cm and 3 cm are given charges of (-1 x 10-2 C) and 5 x 10-2 C , respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 21

Qtotal​ = 4×10−2C

Charge distribution α capacitance α radius

Qsmall​:Qbig​=1:3

Qbig​= 3/4 ×4×10−2 = 3×10−2C

Test: Electrostatic Potential & Capacitance - Question 22

Consider the situation shown in the figure. The capacitor A has a charge q on it whereas B is uncharged. The charge appearing on the capacitor B a long time after the switch is closed is:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 22

Since there is an equal number of positive and negative charges on capacitor A, the charges won't flow to capacitor B as the charge are held by strong electrostatic force.
The capacitor B will acquire a charge only if a battery (driving force) is put in the circuit.

Test: Electrostatic Potential & Capacitance - Question 23

Three capacitors, each of capacitance C = 3 mF, are connected as shown in the figure. The equivalent capacitance between points P and S is ?

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 23

If P is at positive potential, then Q is at negative potential and R is at positive potential. The system therefore reduces to 3 capacitors in parallel. C= 9μF

Test: Electrostatic Potential & Capacitance - Question 24

When two capacitors are put in series, the equivalent capacitance is ________

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 24

When two capacitors C1 and C2 are connected in series, the reciprocal of the equivalent capacitance in series is equal to the sum of the reciprocals of the two individual capacitances.

It has value lesser than the least value of capacitance.

Test: Electrostatic Potential & Capacitance - Question 25

When a capacitor is connected to a battery:

Detailed Solution for Test: Electrostatic Potential & Capacitance - Question 25

When an uncharged capacitor is connected to a battery, charges flow from the poles of the battery to the plates of the capacitor and this process continues till the potential across the capacitor attains the potential difference of the battery. The current flow in the circuit till the time the capacitor is charged and then it ceases.

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