Question

(i) Which property of concave mirror is utilized for using them as shaving mirrors? (ii) Light passes through a rectangular glass slab and through a triangular glass prism. Using proper ray diagram, explain in what way does the direction of the two emergent beams differs with respect to the incident beam of light. (iii) A concave lens has a focal length of 50 cm Calculate its power.

Answer 1

HERE YOUR ANSWER:

( i ). Concave mirror is used as shaving mirror because it forms a magnified and erect image of the face when it is held closer to the face.

( ii ). In a rectangular glass slab, the emergent ray is parallel to the incident ray but they are not along the same line whereas in a prism the emergent ray is not parallel to the incident ray. This is because in a glass block the two surfaces at which refraction occurs is parallel to each other.

( iii ). power of concave lens

f = 50 cm = 0.5 m

formula of lens power is

$p = \frac{1}{f}$

so,

$p = \frac{1}{</strong><strong>0</strong><strong>.</strong><strong>5</strong><strong>}$ = 2 D.

_________________________________

_________________________________

hope it helps you..