79 kj to heat a cup of water?
It requires 79 kJ to heat a cup of water from room temperature to boiling in the microwave oven. If the wavelength of microwave radiation is 2.1×10−3m, how many moles of photons are required to heat the water?
- az_lenderLv 71 month ago
The energy of a single photon is
where h = 6.626 x 10^(-34) J
c = 3.00 x 10^8 m/s and
lambda = 2.1 x 10^(-3) m.
So the energy of 1 photon is around
10^(-22) J but use a calculator.
The energy of a mole of photons will then be
around 60 J, and it will take around 1300 moles of photons to heat the water.
But go back over this using a calculator.