Calculate the time in which 4.8 kJ of energy would be expended when an electric heater of resistance 1.8 x 103Ξ© is used on a 240 V mains supply. (Neglect heat losses to the surrounding).
-
150.0s
- 90.0s
- 36.0s
- 20.0s
- 2.7s.
The correct answer is: A
Explanation
E = V2t/Rt =
ERV2
= 4800 x 1.8 x 103240 x 240
= 150s