A 2 kW boiler used for 1 hour everyday consumes electrical energy in thirty days equal to
120 units
60 units
15 units
40 units
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
1 kWh =
3.6 x 106J
3.6 x 103J
3.6 x 109J
3.6 x 10-3J
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate the cost of electrical energy consumed @ Rs.2.50 per kWh.
Rs.200
Rs.350
Rs.225
Rs.420
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.
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
4
3
5
6
Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
0.727 A
0.625 A
0.825 A
1.35 A
At what voltage is the electric power generated at the power generating station?
11 kV
21 kV
25 kV
40 kV
A switch must be connected in
live wire
neutral wire
earth wire
either live or neutral wire
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
