Question

Microwave ovens emit microwave energy with a wavelength of 12.2 cm. What is the energy of exactly one photon of this microwave radiation?

Answer 1

`1.629xx10^-24J`, rounded to three decimal places.

Explanation:

Let us calculate the frequency `nu` of the photon.
We have the expression between the velocity of light in vacuum `c=nuxxlambda`
or `nu=c/lambda`......(1)

where `lambda` is the wave-length of the electromagnetic radiation. `c=3xx10^8ms^-1`

We also have the expression connecting frequency to energy of photon

`E=hnu` .......(2)

where `h` is Planck's Constant and is `6.626xx 10^-34 m^2 kg s^-1`
From (1) and (2)
`E=hxxc/lambda`
Inserting the constant and given value, after converting wavelength into `m`
`E=6.626xx 10^-34xx(3xx10^8)/0.122`
or `E=1.629xx10^-24J`, rounded to three decimal places.