Question

The radii of curvature of a convex lens is 20 cm and the refractive index of the material of the lens is 3/2. (i) caculate its focal length

Answer 1

I don't know your answer because I am in class 6th you can ask with your other friends or teacher ok

Answer 2

given r=20 CM

as we know that

R = 2f

so , 20 = 2 f

=>20/2=f

=>10=f

I hope this will help you