Question

A binconvex lens have focus 10 cm , refractive index is 1.5, what should be radius of curvature

Answer 1

1/f = (n-1)*(1/R1-1/R2)where n is refractive index which is given 1.5 and R1 and R2 are two radius of curvature of two surface of the lens. Here its biconvex lens so R1 will be positive R and R2 will be negative R.

1/10=(1.5-1)*2/R

or, 1/10=0.5*2/R

or, 1/10=1/R

or, R=10