Coulombs Law Objective Type Questions and Answers

21 If a unit charge is taken from one point to another over an equipotential surface, then

A work is done on the charge

B work is done by the charge

C work on the charge is constant

D no work is done

View Answer

Answer: no work is done

22 The electric field intensity on the surface of a charged conductor is

A zero

B directed normally to the surface

C directed tangentially to the surface

D directed along 45° to the surface

View Answer

Answer: directed normally to the surface

23 A capacitor having a capacitance of 30 μf is connected across a 200 V dc source. The charging current will be least

A initially

B when capacitor is half charged

C when capacitor is fully charged

D when capacitor is almost 90% charged

View Answer

Answer: when capacitor is half charged

24 A sphere of 1 meter radius can attain a maximum potential of

A 1000 V

B 2 kV

C 30 kV

D 3×106 V

View Answer

Answer: 2 kV

25 A capacitor is charged and source is then disconnected. When the plates are now separated

A charge changes

B charge and potential difference both change

C charge and potential difference remain constant

D All Of The Above

View Answer

Answer: charge and potential difference both change

26 The current in a single element circuit leads the voltage 65° at all time. The circuit element is

A A Resistor

B An Inductor

C A Capacitor

D Any Of The Above

View Answer

Answer: A Capacitor

27 The charge on a capacitor is 1.5×10-2 coulombs when the potential difference across its plates is 750 V. The elastance of the capacitor will be

A 0.5 mega daraf

B 1 mega daraf

C 11.2 mega daraf

D None of the above

View Answer

Answer: 0.5 mega daraf

28 The capacitance between two plates increases with

A larger plate area and shorter distance between plates

B shorter plate area and shorter distance between them

C shorter plate area and higher applied voltage

D larger plate area, longer distance between plates and higher applied voltage

View Answer

Answer: larger plate area and shorter distance between plates

29 For a capacitance of 10 μf the potential difference is increased uniformly from 0 to 600 V in 2 seconds. The charging current must be

A 1 mA

B 3 mA

C 5 mA

D All the above

View Answer

Answer: 3 mA

30 For dielectrics, flux is proportional to

A potential difference between electrodes

B resistivity of medium

C rate of change of potential difference

D None Of The Above

View Answer

Answer: potential difference between electrodes

31 Coulomb is the unit of which quantity?

A Field strength

B Charge

C Permittivity

D Force

View Answer

Answer: Charge

32 Coulomb law is employed in

A Electrostatics

B Magnetostatics

C Electromagnetics

D Maxwell’s law

View Answer

Answer: Electrostatics

33 Find the force between 2C and -1C separated by a distance 1m in air(in newton).

A 18 X 106

B -18 X 106

C 18 X 10-6

D -18 X 10-6

View Answer

Answer: -18 X 106

34 Find the force of interaction between 60 stat coulomb and 37.5 stat coulomb spaced 7.5cm apart in transformer oil(εr=2.2) in 10-4 N,

A 8.15

B 5.18

C 1.518

D 1.815

View Answer

Answer: 1.815

35 Two small diameter 10gm dielectric balls can slide freely on a vertical channel. Each carry a negative charge of 1μC. Find the separation between the balls if the lower ball is restrained from moving.

A 0.5

B 0.4

C 0.3

D 0.2

View Answer

Answer: 0.3

36 A charge of 2 X 10-7 C is acted upon by a force of 0.1N. Determine the distance to the other charge of 4.5 X 10-7 C, both the charges are in vacuum.

A 0.03

B 0.05

C 0.09

D All of the above

View Answer