Question

2.5 kg of water at 20°C is heated in an electric kettle connected to 250V supply. If it took 20 minutes to boil at 100°C specific heat capacity of water is 4200JKg⁻¹ k⁻¹. Determine the power of the kettle element. 

Answer 1

Heat gained by water=Mcθ
                               =2.5kg × 4200JKg⁻¹ k⁻¹×80K
                               =840,000J
 P =840000 =700W
       20×60