The focal length of a glass μ=1.5 lens in air is 20 cm. If it is dipped in water μ=43, its focal length in water will be:

1. 80 cm 2. 40 cm
3. 60 cm 4. 20 cm
Subtopic:  Lens Makers' Formula |
 65%
From NCERT
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A plane-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:
1. R/2(μ1 + μ2)
2. R/2(μ1 - μ2)
3. R/(μ1 - μ2)
4. 2R/(μ- μ1)

Subtopic:  Lens Makers' Formula |
 60%
From NCERT
NEET - 2013
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
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To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh