A small plane mirror kept the centre of a sphere of diameter 3 m- makes 12 revolution per second- A thin light beam is made incident on the mirror- The linear speed of the light spot on the sphere- formed after reflection from the mirror is -18pi m-s36pi m-s72pi m-s144pi m-s

Question

Toppr Admin · Accepted Answer

When plane mirror rotates through an angle $θ$ , the reflected ray rotates through an angle 2 $θ$ . So spot on the screen will make 2 x 12 = 24 revolution per second.
To find the velocity
v=2 $π$ R x frequency
=2 $π$ x 3 x 24
=144 $π$ m/s

D is the Correct answer.

A small plane mirror kept at the centre of a sphere of diameter 3 m, makes 12 revolution per second. A thin light beam is made incident on the mirror. The linear speed of the light spot on the sphere, formed after reflection from the mirror is :18π m/s36π m/s72π m/s144π m/s

When plane mirror rotates through an angle θ , the reflected ray rotates through an angle 2θ. So spot on the screen will make 2 x 12 = 24 revolution per second.To find the velocity v=2πR x frequency =2π x 3 x 24=144π m/s D is the Correct answer.

When plane mirror rotates through an angle $θ$ , the reflected ray rotates through an angle 2 $θ$ . So spot on the screen will make 2 x 12 = 24 revolution per second.
To find the velocity
v=2 $π$ R x frequency
=2 $π$ x 3 x 24
=144 $π$ m/s

D is the Correct answer.