Microwave ovens use microwave radiation to heat food. The energy of the microwaves is absorbed by water molecules in food and then transferred to other components of the food.
(a) Suppose that the microwave radiation has a wavelength of 11.2 cm. How many photons are required to heat 200 mL of coffee from 23oC to 60oC?
(b) Suppose the microwave's power is 900 W (1 Watt = 1 Joule-second). How long would you have to heat the coffee in part (a)?