How long does it take a 750W heater to raise the temperature of 1kg of water from 20oC to 50oC [specific heat capacity of water = 4200Jkg-1K-1]
- 84s
- 112s
-
168s
- 280s
The correct answer is: C
Explanation
Heat energy = Elect. energymc\(\theta\) = power x time
1 x 4200 x (50 - 20) = 750 x t
t = 168s