If 0.1 A current flows through a bulb working at 250 V, how many hours are required to consume one unit of electricity?
30 hrs
10 hrs
40 hrs
50 hrs
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
4
3
5
6
At what voltage is the electric power generated at the power generating station?
11 kV
21 kV
25 kV
40 kV
A fuse is used in mains electric supply as a safety device. Which one of the following statements about the fuse is correct?
It is connected in parallel with the main switch.
It is made mainly from silver alloys.
It must have a low melting point.
It must have a very high resistance.
A switch must be connected in
live wire
neutral wire
earth wire
either live or neutral wire
The frequency of AC used in India is
50 Hz
100 Hz
200 Hz
1/100 Hz
At what voltage and frequency is the a.c. supplied to our houses?
220 V, 50 Hz
11 V, 1/50 Hz
220 V, 100 Hz
11 V, 50 Hz
An MCB which cuts off the electrical supply in case of short circuiting or over loading works on the
chemical effect of current
heating effect of current
magnetic effect of current
electroplating effect of current
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
A 100 watt electric bulb is lighted for 2 hours daily and four 40 watt bulbs are lighted for 4 hours everyday. Calculate the energy consumed (in kWh) in 30 days.
25.2 kWh
30.5 kWh
16.5kWh
40.5 kWh
