Physics Friday 43

The average consumer microwave oven uses microwave radiation with a frequency of 2.45 GHz. If you have such an oven running at 1000 W of power (power of the microwaves emmitted into the oven interior), how many photons are emmitted per second?

This is a very simple quantum mechanics problem. The energy of a photon is E=hν. Here, we have photons of frequency ν=2.45×10⁹ Hz. Therefore, the photons have energy E=(6.626×10^-34 J·s)(2.45×10⁹ Hz)=1.62×10^-24 J (=1.01×10^-5 eV).
The power is P=1000 W=1000 J/s, so we have (1000 J/s)/(1.62×10^-24 J)=6.17×10²⁶ photons per second.