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.
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
A switch must be connected in
live wire
neutral wire
earth wire
either live or neutral wire
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be
100 W
75 W
50 W
25 W
A geyser has a rating of 2 kW, 240 V. What is the cost of using it for 30 minutes, if the cost of electricity is Rs.3 per commercial unit?
Rs.3
Rs.6
Rs.9
Rs.15
In what unit does the domestic electric meter measure the electrical energy consumed?
coulomb meter
kilowatt hour
Volt
Joule
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
1 kWh =
3.6 x 106J
3.6 x 103J
3.6 x 109J
3.6 x 10-3J
The electrical appliances in the houses are connected with each other in
parallel
series
a combination of series and parallel circuits
either series or parallel
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
