Current Electricity  MCQs

MCQs of Current Electricity

Showing 71 to 80 out of 119 Questions
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71.
Which of the following is not a unit of mobility ?
(a) m2 V-1 S-1
(b) m2 Ω-1 C-1
(c) C s kg-1
(d) m2 Ω C-1
Answer:

Option (d)

72.
resistivity of material of a conduction wire is 4 × 10-8Ω m. Volume of the wire is 4 m3 and its resistance is 4 Ω. Tehrefore its length will be _____.
(a) 500 m
(b) 5000 m
(c) 20,000 m
(d) 4 × 10-5m
Answer:

Option (c)

73.
Resistivity of a potentiometer wire is 2 × 10-4 Ω m and its cross-sectional area is 1 m2. If mA current is flowing through it, then is potential gradient ?
(a) 2 × 10-1 V/m
(b) 2 × 10-7 V/m
(c) 2 × 107 V/m
(d) 2 × 101 V/m
Answer:

Option (b)

74.
Relation between electric field E, current density J and resistivity ρ is _____.
(a) E=ρ2J
(b) E=ρJ
(c) E=ρJ
(d) E=Jρ
Answer:

Option (b)

75.
Resistance of a wire is R Ω. It is stretched uniformly till its length becomes four times. Its resistivity will _____.
(a) be doubled
(b) be four times
(c) be half
(d) not change
Answer:

Option (d)

76.
J = σE represents _____.
(a) Coulomb's law
(b) Ampere's law
(c) ohm's law
(d) Gauss's law
Answer:

Option (c)

77.
20 Ω resistor wire is bent in the form of a circle. Equivalent resistance between two diametrically opposite point will be _____.
(a) 5 Ω
(b) 10 Ω
(c) 20 Ω
(d) 40 Ω
Answer:

Option (a)

78.
Out of the following, whose temperature coefficient of resistivity is negative ?
(a) Carbon
(b) Fe
(c) Mn
(d) Ag
Answer:

Option (a)

79.
Out of the following , whose resistivity does not reduce to zero at 0º K ?
(a) Pure metal
(b) Nichrome
(c) Cu
(d) Germanium
Answer:

Option (b)

80.
emf of a battery is 2·2 V. When 5 Ω resistor is connected across the battery, its terminal voltage is 1·8 V. Internal resistance of battery = _____ Ω.
(a) 109
(b) 910
(c) 95
(d) 59
Answer:

Option (a)

Showing 71 to 80 out of 119 Questions
5 6 7 8 9 10