Suppose the 1019 photons
(let λ = 650 nm) emitted per second from the 100 W lightbulb
. Suppose all photons are focused onto a piece of black paper and absorbed. Assume that the momentum of a photon changes from p = h/λ to zero
Calculate the momentum of one photon and calculate the force all these photons could exert on the paper.
We use the formula of momentum of a single photon: