JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
A plano convex lens of refractive index \({\mu _1}\) and focal length \(f_1\) is kept in contact with another plano concave lens of refractive index \({\mu _2}\) and focal length \(f_2\). If the radius of curvature of their spherical faces is \(R\) each and \(f_1 = 2f_2\), then \({\mu _1}\) and \({\mu _2}\) are related as
- A \({\mu _1} +2{\mu _2} = 3\)
- B \({2\mu _1} + {\mu _2} = 1\)
- C \({3\mu _2} + {\mu _1} = 1\)
- D \({2\mu _2} + {\mu _1} = 1\)
Answer & Solution
Correct Answer
(A) \({\mu _1} +2{\mu _2} = 3\)
Step-by-step Solution
Detailed explanation
\(\frac{1}{{{f_1}}} = \left( {{\mu _1} - 1} \right)\left( {\frac{1}{R} - \frac{1}{\infty }} \right)\) ; \(\frac{1}{{{f_2}}} = \left( {{\mu _2} - 1} \right)\left( {\frac{1}{\infty } - \frac{1}{R}} \right)\) \(\frac{1}{{{f_1}}} = \frac{{(\mu - 1)}}{R}\) ;…
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