Question

If the radius of curvature of a lens is 30cm,then what is its focal length

Answer 1

Answer:

Correct option is

C

1.33

(1/f)=(n−1)(

R

1

1

−

R

2

1

)

put R

2

→∞ for plane surface

and R

1

=10cm with f=30cm

we get refractive index n=4/3=1.33

Option c is correct.