Figure shows a solid transport semi cylinder of radius `10 cm`. A screen is placed at a distance `60 cm` from `O`. A narrow beam is incident along `X-`axis at `O`. If cylinder starts rotating about `O` in clockwise direction with angular speed `6 rad//s` spot formed on screen will move upward (Refractive index of material of cylinder`=(5)/(3)`)

What is initial angular velcity of ray refrected from plane surface.

Options

A. `100 cm`
B. `80 cm`
C. `120 cm`
D. `100 cm`

Answer

B

Explanation

N//a