Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics
One commercial unit of energy equals
(a) 500 watt-seconds
(b) one watt-hour
(c)One kilowatt-hour
(d) ten kilowatt-hour
The electrical energy required to heat a bucket of water to a certain temperature is 4 kWh. If the heat losses are 20 percent, the energy input is
(a) 2 kWh
(b) 3.2 kWh
(c) 5 k Wh
(d) 6 k Wh
3. The maximum current rating for a 10kฮฉ, 0.5 W resistor is
(a) 0.707 mA
(b) 7.07 mA
(c) 14.14 mA
(d) 28.28 mA
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
The resistance of a conductor varies inversely as
(a) length
(b) area of cross-section
(c) temperature
(d) resistivity
With rise in temperature the resistance of pure metals
(a) Increases
(b) decreases
(c) first increases and then decreases
(d) remains constant
The resistance of a copper wire 200 m long is 21ฮฉ. If its thickness (diameter) is 0.44 mm, its specific resistance is around
(a) 1.2 x 10-8ฮฉ-m
(b) 1.4 x 10-8ฮฉ-m
(c) 1.6 x 10-8ฮฉ-m
(d) 1.8 x 10-8ฮฉ-m
Three resistances of 10 ohms, 15 ohms and 30 ohms are connected in parallel. The total resistance of the combination is
(a)5 ohms
(b) 10 ohms
(c)15 ohms
(d) 55 ohms
9. The resistance of two wires is 25 ฮฉ when connected in series and 6 ฮฉ when joined in parallel. The resistance of each wire is
(a)10 ฮฉ, 15 ฮฉ
(b) 20 ฮฉ, 30 ฮฉ
(c) 5 ฮฉ, 10 ฮฉ
(d) 10 ฮฉ, 20 ฮฉ
10. An instrument which detects electric current is known as
(a) Voltmeter
(b) rheostat
(c) wattmeter
(d) galvanometer
Mam,could u input the solutions of the above problems??