MCQs of Current Electricity

Current Electricity MCQs

MCQs of Current Electricity

Showing 61 to 70 out of 119 Questions

61.

Current density in a copper wire is 2·5 × 10⁸ Am^-2. If 8 A current is flowing through it, the diameter of the wire is _____.

(a)	0·2 mm
(b)	0·02 cm
(c)	0·2 m
(d)	2 mm

62.

Charge passing through the cross section of a conductor is given by Q = B' + A't². What will be the current at time t =10 sec ?

(a)	5A'
(b)	10A'
(c)	20A'
(d)	40A'

63.

Which of the following is a unit of electric resistance ?

(a)	$\frac{1}{C}$
(b)	$\frac{JA}{C}$
(c)	$\frac{J}{CA}$
(d)	$\frac{Ω}{m}$

64.

Four wires are made up of same material _____ wire has maximum resistance.

(a)	short and thick
(b)	short and thin
(c)	long and thick
(d)	long and thin

65.

Length of a wire of resistance R Ω is increased to 10 times, so its resistance becomes 100 Ω, therefore R= _____. (The volume of the wire remains same during increase in the length)

(a)	0·01 Ω
(b)	0·1 Ω
(c)	1 Ω
(d)	10 Ω

66.

When the temperature of a conductor increases, the ratio of its resistivity and conductivity _____.

(a)	decreases
(b)	increases
(c)	remains constant
(d)	increases or decreases

67.

Which one of the following is not a unit of emf of a battery ?

(a)	$\frac{Joule}{Coulomb}$
(b)	Volt
(c)	$\frac{Newton}{Coulomb}$
(d)	$\frac{Newton - metre}{Coulomb}$

68.

Internal resistance of a battery of 2 V terminal voltage is 0·2 Ω. and current flowing it is 0·5 A. So emf of battery will be _____.

(a)	1·9 V
(b)	1·0 V
(c)	2·1 V
(d)	3 V

69.

The ratio of length of two wires of same mass and made up of same material is 1:2. Therefore ratio of their resistance is _____.

(a)	1 : 1
(b)	1 : 2
(c)	2 : 1
(d)	1 : 4

70.

Which is the dimensional formula for conductance from the given below ?

(a)	M¹L²T^-3A^-2
(b)	M^-1L^-2T³A²
(c)	M¹L³T^-3A^-2
(d)	M^-1L^-3T³A²

Showing 61 to 70 out of 119 Questions