Question

A biconvex lens of focal length 10 cm is to be made from a glass material. If the
refractive index of the material is 1.5, what must be the radius of curvature of the
surface of the lens?​

Answer 1

answers

f=( μ_ba-1)(1/r1 – 1/r2)

By using the above formula

μ_ba means refractive index of medium b with respect to medium a ( μb/μa)

In the question it is given that the radius of curvature of the surface of lens need to be found so it means that the radii of curvature of 2 surfaces is same

1/10= (1.5–1)(1/r1+1/r1)

1/10=(0.5)(2/r1)

1/5= 2/r1

R1=10 cm

So the radius of curvature =10 cm

The 2 radii are 10 cm and -10 cm.