MCQs of Current Electricity

Current Electricity MCQs

MCQs of Current Electricity

Showing 91 to 100 out of 119 Questions

91.

A wire has length of

2 \cdot 0

m and a resistance of

5 \cdot 0 Ω .

Find the electric field inside the wire if it carries a current of 10 A.

(a)	$100 \frac{V}{m}$
(b)	$25 \frac{mV}{m}$
(c)	$100 \frac{mV}{m}$
(d)	$25 \frac{V}{m}$

92.

The potential difference between the terminals of a battery is 10 V and internal resistance 1 Ω drops to 8 V when connected across and external resistor. Find the resistance of the external resistor.

(a)	40 Ω
(b)	0·4 Ω
(c)	4 m Ω
(d)	4 Ω

93.

An ideal battery sends a current of 10 A in a resistor. When another resistor of 50 Ω is joined in parallel, the current increases to 30 A. Find the resistance of first resistor.

(a)	10 Ω
(b)	100 Ω
(c)	40 Ω
(d)	30 Ω

94.

A uniform wire of resistance 24 Ω is used to form a regular hexagon ABCDEFA. The equivalent resistance of the loop between A and B is _____Ω.

(a)	4·8 Ω
(b)	3·3 Ω
(c)	48 Ω
(d)	33 Ω

95.

A wire of resistivity

ρ

is stretched to three times its original length. What will be its new resistivity ?

(a)	$ρ$
(b)	$\frac{ρ}{3}$
(c)	$3 ρ$
(d)	Data is not enough

96.

Two wires of equal lengths, one of copper and other of manganin, have the same resistance, then which wire is thicker ?

(a)	Copper
(b)	Manganin
(c)	Both have equal thickness
(d)	None of the above

97.

The resistivity of semiconductors with temperature _____.

(a)	increases
(b)	decreases
(c)	does not change
(d)	None of the above

98.

Resistivity of the material of potentiometer wire is

ρ

and area of its uniform cross section is A. hence potential gradient on the wire is _____.

(a)	$IAρ$
(b)	$\frac{IA}{ρ}$
(c)	$\frac{I}{ρ A}$
(d)	$\frac{I ρ}{A}$

99.

Which unknown quantity is measured with the help of Wheatstone's Bridge ?

(a)	Electric curerent
(b)	Voltage
(c)	resistance
(d)	emf

100.

If a wire of resistance R is melted and recasted to half of its length, then the resistance of the wire will be _____.

(a)	$\frac{R}{4}$
(b)	$\frac{R}{2}$
(c)	$R$
(d)	$2 R$

Showing 91 to 100 out of 119 Questions