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The refractive index and the focal lengt...

The refractive index and the focal length of a plano convex lens are 1.5 and 50 cm respectively. What is the radius of curvature of the curved surface ?

A

10 cm

B

15 cm

C

20 cm

D

25 cm

Text Solution

Verified by Experts

The correct Answer is:
D
For a plano convex lens, `R_(1)=R and R_(2)=oo`
`therefore (1)/(R_(2))=0 therefore (1)/(f)=(n-1)xx (1)/(R )`
`therefore (1)/(50) =(1.5-1)(1)/(R )=(1)/(2R)`
`therefore 2R=50 therefore R=25 cm`
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