posted by andrea .
Microwave ovens use microwave radiation to heat food. The microwaves are absorbed by moisture in the food, which is transferred to other components of the food. As the water becomes hotter, so does the food. Suppose that the microwave radiation has a wavelength of 11.2 cm
How many photons are required to heat 200 mL of coffee from 24C to 63C
q to heat 200 mL H2O = mass water x specific heat water x delta T water. = 200 g x 4.184 x (63-24) = xx joules.
E in a 11.2 cm photon.
E = hc/wavelength.
E = h is Planck's constant. c is speed of light in m/s and wavelength is in 11.2 cm convert to meters. This will be the energy of 1 photon of the 11.2 cm wavelength. Then E joules/photon x # photons = xx joules. Solve for # photons.