JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
Curved surfaces of a plano-convex lens of refractive index \(\mu_{1}\) and a plano-concave lens of refractive index \(\mu_{2}\) have equal radius of curvature as shown in figure. Find the ratio of radius of curvature to the focal length of the combined lenses.
- A \(\frac{1}{\mu_{2}-\mu_{1}}\)
- B \(\mu_{1}-\mu_{2}\)
- C \(\frac{1}{\mu_{1}-\mu_{2}}\)
- D \(\mu_{2}-\mu_{1}\)
Answer & Solution
Correct Answer
(B) \(\mu_{1}-\mu_{2}\)
Step-by-step Solution
Detailed explanation
\(\frac{1}{{f}_{1}}=\left(\mu_{1}-1\right)\left(\frac{1}{{R}}\right)\) \(\frac{1}{{f}_{2}}=\left(\mu_{2}-1\right)\left(-\frac{1}{{R}}\right)\) \(\frac{1}{{f}_{1}}+\frac{1}{{f}_{2}}=\frac{1}{{f}_{{eq}}}=\frac{\left(\mu_{1}-1\right)-\left(\mu_{2}-1\right)}{{R}}\)…
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