Q. 78

Expert-verified
Found in: Page 994

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A spherical mirror of radius R has its center at C, as shown in FIGURE P34.78. A ray parallel to the axis reflects through F, the focal point. Prove that f = R/2 if

The statement is proved.

See the step by step solution

## Step 1: Given information

We have given,

A ray incident parallel to the principle axis and reflects through F.

we have to prove

## Step 2: Simplify

According to the law of reflection

incident angle = Reflected angle

As incident angle is parallel to the principle axis.

then using the figure, we can say that the alternative angles are equal.

since two angle of the triangle are equal then we can say that it is a isosceles triangle.

CF=FA

and CM=MA=

since pole to C length is R.

since,

then we write,