Question

An electric kettle is rated at 500watt.the time taken to heat 0.5 litre of water from 30 degree celsius to 100 degree celsius in this kettle is?

Answer 1

Power of cattle  p= 500w 

working v=200v

heat developed in 30s

h=pt, 500*30=15000j

let delta t be rise in tamp: of water 

therefor 

h=m*s*delta t

15000=0.4*4200*delta t

delta t = 8.93 deg centigrade.

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