A point object is kept in air at 40 cm in front of an equiconvex lens silvered on one side. Radius of curvature of each side of lens is 20 cm and refractive index of lens material is 3/2. Where is the final image formed from silvered lens?
A
60 cm
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B
307 cm
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C
90 cm
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D
407 cm
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Solution
The correct option is D407 cm
Focal length of mirror;fm=−202 cm=−10 cm
Focal length of lens 1fl=[μ−1][1R1−1R2]=[32−1][120−−120] ∴fl=20 cm
We know for combination of lens and mirror 1v+1u=1fm−2fl 1v+1−40=1−10−220 v=−407 cm