Question 173: Ray Optics

Question

A plano convex lens of refractive index $$\mu $$
1
and focal length ƒ
1
is kept in contact with another plano concave lens of refractive index $$\mu $$
2
and focal length ƒ
2
. If the radius of curvature of their spherical faces is R each and ƒ
1
= 2ƒ
2
, then $$\mu $$
1
and $$\mu $$
2
are related as -

Accepted Answer

$${1 \over {2{f_2}}} = {1 \over {{f_1}}} = \left( {{\mu _1} - 1} \right)\left( {{1 \over \infty } - {1 \over { - R}}} \right)$$
$${1 \over {{f_2}}} = \left( {{\mu _2} - 1} \right)\left( {{1 \over { - R}} - {1 \over \infty }} \right)$$
$${{\left( {{\mu _1} - 1} \right)} \over R} = {{\left( {{\mu _2} - 1} \right)} \over {2R}}$$
$$2{\mu _1} - {\mu _2} = 1$$

Answer

$$3{\mu _2} - 2{\mu _1}$$ = 1

Answer

$${\mu _1} + {\mu _2}$$ = 3

Answer

$$2{\mu _1} - {\mu _2}$$ = 1

Answer

$$2{\mu _2} - {\mu _1}$$ = 1

Ray Optics

A plano convex lens of refractive index $\mu 1 and focal length ƒ 1 is kept in contact with another plano concave lens of refractive index \mu 2 and focal length ƒ 2 . If the radius of curvature of their spherical faces is R each and ƒ 1 = 2ƒ 2 , then \mu 1 and \mu $ 2 are related as -

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