Physics M.C.Q (1 Marks)

3. Both static and dynamic electric field.

Explanation:
An electric potential can be calculated in either a static (or time invariant) or a dynamic (varying with time) electric field at a specific time in units of Joules per Coulomb or Volts.

2. Dielectric

Explanation:
A dielectric is a substance which does not allow the flow of charges through it but permits them to exert electrostatic forces on one another through it. A dielectric is essentially an insulator which can be polarized through small localized displacements of its charges.

3. Van de Graff generator is used to create a large amount of static electricity.

Explanation:
Van de Graff generator is used to create a large amount of static electricity. A Van de Graff generator uses static electricity and a moving belt to charge a large metal sphere to a very high voltage. As the belt moves, electrons move from the rubber belt to the silicon roller, causing the belt to become positively charged and the roller to become negatively charged. As a result, it builds up positive charge.

3. Both A and B false.

Explanation:
Positive charges move from higher to lower potential whereas negative charges move from lower to higher potential. Hence, A is false. Electric potential does not have direction and is a scalar quantity.

2. Remains unchanged.

2. VA - VB = 0.

4. Increases.

2. Uniform

Explanation:
The direction of the electric field is from the positive to the negative plate. In the inner region, between the two capacitor plates, the electric fields due to the two charged plates add up. Hence, the field is uniform throughout.

3. Farad.

3. 2C

Explanation:
For IMAGE 01 AND 02:
[Loops AXBY forms wheat stone bridge ]
So, effective capacitance will be for the bridge C
In IMAGE 03 the parallel combination 
C′ = C + C = 2C

2. Forces between charges in rest.

2. B

Explanation:
A charged species tends to move from place of higher potential energy to that of lower potential energy.
The direction of electric field is from left to right. This means that there is a positively charged plate on the left side, closest to A and farthest from B.
An electron being negatively charged plate always moves towards left here.

2. Potential difference between two points.

2. 10V.

3. Zero

Explanation:
In the outer regions above the upper plate and below the lower plate, the electric fields due to the two charged plates cancel out. Hence, the net electric field in the outer regions above the plate and below the lower plate is zero.

1. Mica

Explanation:
Dielectric constant is the factor by which the capacitance increases from its value in air when a dielectric is introduced between the plates.
Mica, among the materials mentioned above, is a dielectric material and hence to be used to increase the capacity.

4. Both the statements (a) and (b) are correct.

Explanation:
The magnitude of electric field is given as the change in magnitude of potential per unit displacement as

2. Equipotential surface.

4. Zero

Explanation:
The potential difference between any two points on an equipotential surface is zero.
Work done = Test charge x potential difference(0)

1. −15C is at higher potential.

Explanation:
Potential at surface of a sphere of radius r is V = kQ/ r
As identical sphere so r is same for both, Thus V will depend on charge Q.
So when Q is more, potential will be more.
Since −15 C is more than −16 C, so −15 C sphere will have higher potential.

2. Electrostatic potential = Work done/ charge

Explanation:
The formula for electrostatic potential is Electrostatic potential = Work done/ charge.

3. Equipotential surface is on yz plane.

Explanation:
Electric potential of every point  lying on the YZ  plane is zero as every point is at equal distance from negative and positive charge of dipole. So, the plane will be equipotential.

2. Decreases.

3. Both a and b

2. The electric field is zero.

4. I, II and III.

4. [L-2 A T]

3. The surface of a charged conductor is equipotential.

Explanation:
In conductors, charges are equally distributed over the surface of the conductor. Therefore the potential throughout the surface is the same, i.e. equipotential. The electric field is a vector quantity and the field lines cut the equipotential surfaces at 90 degrees. The field lines due to a point charge are radial.

4. Neither (a) nor (b).

2. Electrostatic shielding

Explanation:
The phenomenon of making a region free from any electric field is called electrostatic shielding. It is based on the fact that the electric field vanishes inside the cavity of a hollow conductor.

3. Non-polar

Explanation:
A molecule in which the centre of mass of positive and negative charges collide with each other is called a non-polar molecule. They normally have zero dipole moment. They have symmetrical shapes.

1. A Van de Graff generator produces large voltage and less current.

Explanation:
A Van de Graff generators produces large voltage and less current. A Van de Graff generator is an electrostatic generator which creates very high electric potentials. It produces very high voltage direct current electricity at low current levels.

4. Dielectric strength.

2. Dielectric strength.

3. Both a and b.

4. Electric field varies within the cube.

2. Permanent dipole moment.

3. Potential energy

Explanation:
The work done against electrostatic force gets stored in the form of potential energy.

1. Volt

Explanation:
Unit of electric potential difference is volt(V).

1. Potential

Explanation:
When there is a temperature difference, heat flows from high temperature to low temperature. Similarly, when there is a potential difference electric current flows from high potential to low potential. Hence, potential is analogous to temperature.

2. Decreases.

4. No work is done.

3. Zero

Explanation:
Net electrostatic field is zero in the interior of a conductor. When a conductor is placed in an electric field, its free electrons begin to move in the opposite direction. Negative charges are induced on the left end and positive charges on the right end of the conductor. The process continues until the electric field set up by induced charges becomes equal and opposite the external field.