Basic Electrical Science (Work, Power and Energy)

1.   If a 220 V heater is used on 110 V supply, heat produced by it will be------as much.
(a) one-half
(b) twice
(c) one-fourth
(d) four times

2.   For a given line voltage, four heating coils will produce maximum heat when connected
(a) all in parallel
(b) all in series
(c) with two parallel pairs in series
(d) one pair in parallel with the other two in series

3.   The electric energy required to raise the tem­perature of a given amount of water is 1000 kWh. If heat losses are 25%. the total heat­ing energy required is—kWh.
(a) 1500
(b) 1250
(c) 1333
(d) 1000

4.   One kWh of energy equals nearly
(a) 1000 W
(b) 860kcal
(c) 4186 J
(d) 735.5 W

5.   One kWh of electric energy equals
(a) 3600 J
(b) 860kcal
(c) 3600 W
(d) 4186 J

6.   A force of 10.000 N accelerates a body to a velocity 0.1 knis. This power developed is ------kW
(a) 1,00,000
(b) 36,000
(c) 3600
(d) 1000

7.   A 100 W light bulb burns on an average of 10 hours a day for one week. The weekly
consumption of energy will be------unit's
(a) 7
(b) 70
(c) 0.7
(d) 0.07

8.   Two heaters, rated at 1000 W, 250 volts each, are connected in series across a 250 Volts 50 Hz A.C. mains. The total power drawn from the supply would be---------watt.,
(a) 1000
(b) 500
(c) 250
(d) 2000