SI unit of electrical energy
Watt
Calorie
Joule
Kilowatt hour
Two bulbs are marked 60 W, 220 V and 60 W, 110 V respectivelly. The ratio of resistance is:
4:1
2:1
2:4
4:3
Circuit breaker device which can be used in place of fuse wire in domestic electric wiring is called
CBD
DCB
MCD
MCB
According to International convention of colour coding of insulation of wires in a cable :
live is red, neutral is blue and earth is brown
live is red, neutral is green and earth is black
live is brown, neutral is blue and earth is black
live is brown, neutral is light blue and earth is green
Factors which does not affect heat dissipation by a conductor is:
current
time
resistance
voltage
1 kWh =
3.6 J
3.6 x 106 J
3.6 x 10-6 J
3600 J
Current through a 12 V tungsten filament lamp connected to a 12 V accumulator of negligible resistance of 3 A. Calculate resistance of filament?
4 Ω
6 Ω
12 Ω
24 Ω
Fuse is always connected in
live wire
neutral
earth
none of these
The energy used in households, industries and commercial establishments are usually expressed in
Kilowatt - hour
volt
The bulb is rated as 100W - 250V, the resistance of its filament while glowing is,
100 Ω
250 Ω
625 Ω
2500 Ω
