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Focal length of a convex lens of refract...

Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal length of lens when immersed in a liquid of refractive index 1.25 will be

A

10 cm

B

2.5 cm

C

5 cm

D

7.5 cm

Text Solution

Verified by Experts

The correct Answer is:
C
`(f_(1))/(f_(a)) = (n_(ga) - 1)/( n_(gl) - 1) rArr (f_(1))/(2) = (1.5 - 1)/((1.5)/(1.25) - 1) rArr f_(1) = 5 `cm .
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