A concave mirror has a focal length of 25 cm. A person wants to see his face in this mirror. At what distance should the person stand ? 

For a point object or for a small finite object, the focal length of a small spherical mirror is related to object distance and image distance as, \(\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\)

Correct option is A) f

C) brightness reduced

B) the mirror and the screen

B) on the same wall as the window

D) The mirror and the screen

B) a mirror holder, a screen holder and a scale

Correct option is C) – 54 cm

Correct option is A) 12 cm

Correct Answer - A (b)