Question

The radii of curvature of the phases of double convexes are 10cm and 15 cm. If focal length is 12cm find refractive index..​

Answer 1

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Given

R1 = 10 cm

R2 = 15 cm

f = 12 cm

Solution

focal length of double convex lens is

1/f = (n-1) (1/R1 -;1/R2)

1/12 = (n-1) (1/10 - 1/15)

1/12 = (n-1) × 1/30

n - 1 = 30/12

n - 1 = 2.4

n = 3.4

Answer 2

Answer:

Given:-

R1= 10cm

R2 = 15cm

f=12cm

Find:-

Refractive index

Solution:-

focal length of double convexes lens is

1/f = (n-1) (1/R1 - 1/R2)

1/12 = (n-1) (1/10 -1/15)

1/12 = (n-1) (1/30)

n-1 = 30/12

n -1 = 2.4

n= 3.4