Question

A light ray parallel to the principal axis reflected from the concave mirror

Draw the reflected ray and show the directions.

please give answer properly ​

Answer 1

Answer:

A ray of light parllel to principal axis (shows that u=∞) after reflection from concave mirror (of focal length f) passes through.

  u−1+v1=f1

So  ∞−1+v1=f−1

 v1=f−1

v=−f

i.e. it passes through focus.

Answer 2

A ray of light parllel to principal axis (shows that u=∞) after reflection from concave mirror (of focal length f) passes through.

$\frac{ - 1}{u} + \frac{1}{v} = \frac{1}{f} \\ \\ \frac{ - 1}{ \infty } + \frac{1}{v} = \frac{ - 1}{f} \\ \\ \frac{1}{v} = \frac{ - 1}{f} \\ \\ v = - f$

i.e. it passes through focus.