Question

If one surface of a double convex lens has been
silvered then its effective focal length f is (take
refractive index of material as u and radius of
curvature of either surface as R)
R.
(1)
RC 3
(2)
M-2
R
R.
(3)
(4)
4u-2
2u​

Answer 1

Answer:

Given

Radius of curvature =R

focal length =f

Refractive index, μ=1.5

From lens maker's formula

f

1

=(μ−1)[

R

1

1

−

R

2

1

]

f

1

=(1.5−1)[

R

1

+

R

1

]

=0.5×

R

2

f

1

=

R

1

f=R