A microwave oven heats food using electromagnetic waves (with wavelengths in the microwave regime). In this problem, we'll estimate the sizes of the electric and magnetic fields involved.
a) One cup (a specific measurement used for cooking) is a volume of about 230 mL. Estimate the amount of time it takes to heat one cup of water in the microwave from room temperature to boiling. (You may want to experiment with your own microwave if you don't already have a good idea of this.) From this time estimate, determine the power that the oven delivers to the water, in watts (joules/s). (Hint: how do you find the amount of energy needed to raise the temperature of a certain mass of water by a certain amount? Review Ch. 17 if necessary.)
b) Assuming electromagnetic radiation is flowing into the cup inside the microwave from all sides, estimate the electromagnetic energy flux, S, in W/m2.
c) From the flux you calculated, estimate the strength of the electric and magnetic fields in the microwave oven.