Hey jiskha.

Microwave ovens emit microwave radiation that is absorbed by water. The absorbed radiation is converted to heat that is transferred to other components of the food. Suppose that the microwave radiation has a wavelength of 12.7 cm. How many photons are required to heat 200. mL of coffee from 21°C to 63°C?

I have no clue where to start.

2 answers

No
E = hc/wavelength = xx J energy of 1 photon.

How much energy do you need?
q to heat coffee. = mass water x specific heat water x delta T = ?? joules total needed.

so how many of those photons will you need?

?? J/photon x # photons = ??total joules needed.
So you