Physics - Geometrical Optics Question with Solution | TestHub

A mirror turning at $\omega$ turns the reflected beam by $2\omega$.

Disks rotate in opposite directions, so each reflection adds $2\omega$ in the same sense.

After 1 reflection: $2\omega$.

After 2: $2\omega +2\omega =4\omega$.

After $n$ reflections: $\Omega =2n\omega$.