Focal length of the combination f1=f11+f21 We have f1=(μ1−1)R and f2=(μ2−1)R or f11=(μ1−1)R or f21=−(μ2−1)R Putting these values in Eq. (i), we get f1=R(μ1−1)−R(μ2−1)=R[μ1−1−μ2+1]=Rμ1−μ2
A plano-convex lens fits exactly into a plano-concave lens. Their plane surfaces are parallel to each other. If lenses are made of different…
NEET UG 2013 — Physics Optics
2013mcqhard
A plano-convex lens fits exactly into a plano-concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices μ1 and μ2 and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is
Official previous-year question
Held on 30 Apr 2013 · Verified 9 Jul 2026.
Options
- A
2(μ1+μ2)R
- B
2(μ1−μ2)R
- C
(μ1−μ2)R
- D
(μ2−μ1)2R
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