engineering recuitment BARC Stipendiary Trainee Category I 2023 Mock Test Physics Ray Optics Refraction and Reflection
The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, then focal length of lens will be:
1
20 cm
2
-20 cm
3
-40 cm
4
40 cm