Question 410: Ray Optics

Question

For a plano convex lens ($$\mu $$ = 1.5) has radius of curvature 10 cm. It is silvered on its plane surface. Find focal length after silvering

Accepted Answer

$${1 \over f} = \left( {\mu  - 1} \right)\left( {{1 \over {{R_1}}} - {1 \over {{R_2}}}} \right)$$
= $$\left( {1.5 - 1} \right)\left( {{1 \over \infty } - {1 \over { - 10}}} \right)$$ = $$0.5\left( {{1 \over {10}}} \right)$$
$$ \Rightarrow $$ f = 20 cm
When plane surface is silvered, F = $${f \over 2} = {{20} \over 2}$$ = 10 cm

Answer

10 cm

Answer

20 cm

Answer

15 cm

Answer

25 cm

Ray Optics

For a plano convex lens ($\mu $ = 1.5) has radius of curvature 10 cm. It is silvered on its plane surface. Find focal length after silvering

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