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# MCQ on Electrostatics

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1) Which of the following is a vector quantity

1. electrical potential
2. electrical field intensity
3. electric charge
4. none of the above
EXPLANATION
No answer description required for this question.

2) The unit of field intensity is

1. coulomb
2. coulomb/m2
3. webber
4. newton/coulomb
EXPLANATION
Electric field intensity is the force experienced by a test charge Q in a electric field E. So, its unit is (N/C).

3) Coulomb’s law for the force between electric charges most closely resembles with

1. newton law of motion
2. law of conversation of energy
3. Gauss theorem
4. newton law of gravitation
EXPLANATION
No answer description required for this question.

4) Two capacitor of each breakdown voltage 500 V are connected parallel. The breakdown rating of the combination will be

1. 500 V
2. 500√2 V
3. 1000 V
4. 2500 V
EXPLANATION
When 2 capacitors are connected in parallel, the voltage rating will be the equal to the lowest rated capacitor voltage.Here, both capacitors of are equal value, that’s why we can apply voltage up to 500 V.

5) A charge which when placed in vacuum from an equal and similar charge repels with a force of 9000 N, is known as

1. coulomb
2. milli coulomb
3. micro coulomb
4. pico coulomb
EXPLANATION
According to the Coulomb’s law,

Q= (Force×Distance2)/k

Where, (Force×Distance2) = Newton

So, Q=N/k         (k=9×109 )

Q= (9×103)/(9×109)= 1×10-6

6) Another name for relative permittivity is

1. dielectric constant
2. dielectric strength
4. none of the above
EXPLANATION
No answer description required for this question.

7) Electric lines of force about a negative point charge are

1. circular, anticlockwise
2. circular, clockwise
EXPLANATION
Lines of force originate from a positive charge and terminate to a negative charge, means it moves inward towards the negative point charge.

8) Two charges are placed at a certain distance apart. A brass sheet is placed between them. The force between them will

1. increase
2. decrease
3. remains unchanged
4. none of the above
EXPLANATION
No answer description required for this question.

9) When the relative permittivity of the medium is increased, the force between two charges placed at a given distance apart

1. increases
2. decreases
3. remains the same
4. none of the above
EXPLANATION
Force between two charges in a medium is given by:

F= 9×109 × (q1q2)/(εrd2)

It is clear that force is inversely proportional to the relative permittivity of the medium in which the charges are placed. Therefore, the force decreases.

10) As one penetrates a uniformly charged sphere, the electric flied strength E

1. increases
2. decreases
3. is zero at all points
4. remains same as at surface
EXPLANATION
No answer description required for this question.

11) A point charge in space is attracted towards a dielectric material because of the

1. phenomenon of dielectric polarization
2. maximization of electrostatics flux
3. dielectric hysteresis
4. none of the above
EXPLANATION
Due to the surface charge density, the particle of a dielectric material carrying the same sign of charge and it is being attracted to one another. Since, the electrostatic flux is directly proportional to the charge density and thus due to the maximization of electrostatic flux that point charge is attracted towards a dielectric material.

12) A region around a stationary electric charge has

1. magnetic field
2. electric field
3. both electric and magnetic field
4. neither electric nor magnetic field
EXPLANATION
When charge particle is in stationary position ,an electric field surrounds it .
When  charge particle starts moving , a magnetic field surrounds it.

13) A charged oil drop is stationary between a pair of horizontal parallel plates. If the drop carries a charge 3.2×10-10 coulomb and has a mass 1.6×10-19 kg, then the potential difference between the plates is

1. 50 V
2. 80 V
3. 100 V
4. cannot be calculated on the basis of given data
EXPLANATION
No answer description required for this question.

14) The force of attraction or repulsion between two charges q1 and q2 at a distance d meters apart is proportional to the product of charges q1 and q2 and is inversely proportional to the distance square between the two charges. Above statement is attributed as:

1. Lenz’s law
3. Coulomb’s law
4. Maxwell’s law
EXPLANATION
No answer description required for this question.

15) A positive and a negative charge are initially 4 cm apart. When they are moved closer together so that they are now only 1 cm apart, the force between them will be

1. 16 times larger than before
2. 8 times larger than before
3. 4 times larger than before
4. 4 times smaller than before