The Student Room Group

Photon between two mirrors



Having some issues with this question, both parts really. For the first part I think you have to calculate the maximum energy somehow and then use that to calculate the wavelength using hc/E . But not really sure how to calculate the energy

As for the second part im not really sure at all, it's perhaps related to the change in momentum? but again not sure

Dont think it's relevant but above, the energy of a photon released in the photoelectric effect on aluminum was calculated to be 4.1eV, hence I was also able to calculate it's frequency, but I think this is unrelated
Reply 1
Im just guessing here, but that 4.1eV could be the energy that would be absorbed by the mirror, as any photon with a higher energy may be sufficient to be absorbed to release a photoelectron. So with the maximum energy for reflection, we can work out the minimum wavelength for reflection via wavelength=hc/E. So I think it may be relevant - there doesnt seem to be anywhere else to go from.

As for the second part, you could calculate the momentum of the photon by (mv)=h/wavelength. Then with the momentum and f=mv/t, use the speed of light and divide that by the seperation 10^-6, you will be left with a value in the units s^-1, then multiply the momentum by this value to get the force.

I hope this helped, not sure if it is right at all - but I thought I'd have a shot.

Quick Reply

Latest