Question

the focal length of convex length is equal to the radius of curvature of eaither face , what is the refractive index of the material of the lens​

Answer 1

Answer:

focal length of a lens is given by:

1/f = (u-1) (1/r1 + 1/r2)

by the iven information we have got

r1 = r2= f = r

1/r = (u -1) (1/r + 1/r)  

or

u = 1/2 + 1

= 3/2

= 1.5

Explanation: