Question 296: Ray Optics

Question

A biconvex lens has radii of curvature, 20 cm each. If the refractive index of the material of the lens is 1.5, the power of the lens is

Accepted Answer

Power of lens is given by
$$P = {1 \over {f(m)}}$$
$${1 \over f} = (\mu  - 1)\left( {{1 \over {{R_1}}} - {1 \over {{R_2}}}} ight)$$
$${1 \over f} = \left\{ {{3 \over 2} - 1} ight\}\left( {{1 \over {20}} + {1 \over {20}}} ight)$$
$$f = 20$$ cm
$$P = {1 \over {20 	imes {{10}^{ - 2}}}}$$
$$ = 5$$ D

Answer

+2 D

Answer

+20 D

Answer

+5 D

Answer

Infinity

Ray Optics

A biconvex lens has radii of curvature, 20 cm each. If the refractive index of the material of the lens is 1.5, the power of the lens is

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