Physics, asked by vatsalpatni, 10 months ago

A beam of light after reflection from a plane mirror falls on a circular scale 1.5 m from the mirror. On slightly rotating the mirror, the light spot on the scale moves through 10 cm. What is the angle of rotation of the mirror? Assume that the mirror is almost at the centre of the circular scale.​

Answers

Answered by SweetLily
2

Solution

  • If the mirror rotates through angle θ , then the reflected ray will also rotate through 2θ.

➣Movement of the spot = arc (circular scale)

➣Movement of the spot = radius× 2θ

\sf{➛150× 2θ= 10}

\sf{➛θ=\dfrac{10}{300} radian}

we know that π radian =180 degree

so

\sf{\dfrac{10}{300} radian = \dfrac{10}{300}  ×\dfrac{180}{π} =1.9°}

Hence the mirror rotates through 1.9°

Similar questions