Amichelson interferometer is an optical instrument which works on the principle of constructive/destructive interference of waves which travel a different distance (introducing a phase difference). would such an instrument work on sunlight? why or why not? could you build an rf equivalent?

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?