Question

A monochromatic red laser beam emitting 1 mW at a wavelength of 638 nm is incident on a silicon solar cell. Find the following: a. The number of photons per second incident on the cell b. The maximum possible efficiency of conversion of this laser c. beam to electricity

Answer 1

Answer:

Explanation:

First we calculate the energy of the photon

E=(Planck constant × speed of light in vacuum)÷ wave length

E=$\frac{6.626*10^{34}*2.998*10^{8} }{638*10^{-9} } = 3.114*10^{49}$

Next we find the total energy per second

total energy= $1*10^{-3}W *\frac{1JS^{-1} }{1W} = 1*10^{-3} JS^{-1}$

Next we calculate the number the photon per second

= total energy ÷ energy of 1 photon

= $\frac{1*10^{-3} JS^{-1} }{3.114*10^{49} } = 3.21*10^{-53} \ photons/sec$