Question

Through what angle a mirror is rotated about an axis passing through the point of incidence and in the plane of mirror so that the reflected ray is rotated through an angle of 40°.​

Answer 1

Answer:

I hope it will give you answer

Answer 2

The reflected ray is rotated by twice the angle

Explanation:

• On rotating the plane mirror , the angle of incidence ( i ) now becomes (2i) . So it basically because double the original incident angle.
• The reflected ray will be rotated through an angle 2r, where r is the initial angle of reflection.
• Therefore in this case , the reflected ray will be rotated through an angle , $2\times 40 = 80$°.
• Answer will be $80$° .
• An image has been attached for better understanding of how the reflected angle should become twice the initial angle of reflection.