Question

1.0 kg of water is container in a 1.25 kW kettle Calculate the time taken for the temperature of water to rise from 25° C to its boiling point 100°C. Specific heat capacity of water = 4.2 J g^-1K^-1 

Answer 1

Mass of water = 1000 g.

Change in temperature=100^oC − 25 ^oC = 75 ^oC (or 75K)

Amount of heat energy required to raise temperature = 1000 × 4.2 × 75 = 315000 J.

Time taken to raise the temperature, T = 4 min 12 seconds.