- Technical Blog From My Notebook

## Current Electricity objective questions in Electrical Engineering

The substances which have a large number of free
electrons and offer a low resistance are called
(a) insulators
(b) inductors
(c) semi-conductors
(d) conductors
Ans: d

Out of the following which is not a poor conductor ?
(a) Cast iron
(b) Copper
(c) Carbon
(d) Tungsten
Ans: b

Out of the following which is an insulating material ?
(a) Copper
(b) Gold
(c) Silver
(d) Paper
Ans: d

Conductance is reciprocal of
(a) resistance
(b) inductance
(c) reluctance
(d) capacitance
Ans: a

With rise in temperature the resistance of pure metals
(a) increases
(b) decreases
(c) first increases and then decreases
(d) remains constant
Ans: a

With rise in temperature the resistance of semiconductors
(a) decreases
(b) increases
(c) first increases and then decreases
(d) remains constant
Ans: a

The resistance of a copper wire 200 m long is 21 Q. If its
thickness (diameter) is 0.44 mm, its specific resistance is
around
(a) 1.2 x 10~8 Q-m
(b) 1.4 x 10~8 Q-m
(c) 1.6 x 10″”8 Q-m
(d) 1.8 x 10″8 Q-m
Ans: c

An instrument which detects electric current is known
as
(a) voltmeter
(b) rheostat
(c) wattmeter
(d) galvanometer
Ans: d

A light bulb draws 300 mA when the voltage across it is
240 V. The resistance of the light bulb is
(a) 400 Q
(b) 600 Q
(c) 800 Q
(d) 1000 Q
Ans: c

In a circuit a 33 Q resistor carries a current of 2 A. The
voltage across the resistor is
(a) 33 V
(b) 66 v
(c) 80 V
(d) 132 V
Ans: b

Four wires of same material, the same cross-sectional
area and the same length when connected in parallel give a
resistance of 0.25 Q. If the same four wires are connected is
series the effective resistance will be
(a) 1 Q
(b) 2 Q
(c) 3 Q
(d) 4 Q
Ans: d

Which of the following material has nearly zero
temperature co-efficient of resistance?
(a) Manganin
(b) Porcelain
(c) Carbon
(d) Copper
Ans: a