Question:medium
Two plano-concave lenses (1 and 2) of glass of refractive index 1.5 have radii of curvature 25 cm and 20 cm. They are placed in contact with their curved surfaces towards each other and the space between them is filled with liquid of refractive index 4/3. The combination is
Two plano-concave lenses (1 and 2) of glass of refractive index 1.5 have radii of curvature 25 cm and 20 cm. They are placed in contact with their curved surfaces towards each other and the space between them is filled with liquid of refractive index 4/3. The combination is
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For lenses in contact with a medium:
Pₙet = sum Pₛᵤᵣfₐcₑₛ
Always consider refractive index of the filling medium.
Updated On: Mar 20, 2026
- convex lens of focal length 70 cm
- concave lens of focal length 70 cm
- concave lens of focal length 66.6 cm
- convex lens of focal length 66.6 cm
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The Correct Option is C
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