Question

Now instead a 3-mw laser of wavelength λ = 760 nm is directed into the interferometer (with the mirror m1 at the displacement calculated in part a). how much power is detected at d1?

Answer 1

power received will always remain same and does not depends on the distance

it will be same as the power of source

`P = 3 mW`

now the energy released by one photon is given as

`E = (hc)/(\lambda)`

`E = (6.6* 10^(-34)* 3 * 10^8)/(760 * 10^(-9))`

`E = 2.6 * 10^(-19) J`

now let say N photons per second released

`N * 2.6 * 10^(-19) = 3 * 10^(-3)`

`N = 1.15* 10^(16) per\: second`