Question

an ice cube placed in microwave melts in five minutes and it takes 3.50 kj of energy to melt it. what is the power of the microwave?

Answer 1

If the ice absorbed 350,000 joules in 5 minutes, then it absorbed energy
at the rate of

   (350,000 joules) / (5 x 60 seconds)  =  1,166-2/3 watts .

Surely the ice cube didn't absorb every joule delivered to the cooking chamber,
so the microwave oven's cooking power had to be significantly more than that.