Answer & explanation
Correct answer: option 1
$\text{If mirror makes n revolution per second then the reflected ray will make 2n revolution per second}$
$\text{Speed of light on Screen is} 2n \times 2\pi R = 4n\pi R$
Correct answer: option 1
$\text{If mirror makes n revolution per second then the reflected ray will make 2n revolution per second}$
$\text{Speed of light on Screen is} 2n \times 2\pi R = 4n\pi R$