Question
Question: A plano-convex lens is made of a material of refractive index 1.5. The radius of curvature of curved...
A plano-convex lens is made of a material of refractive index 1.5. The radius of curvature of curved surface is 20 cm. If plane surface is silvered The focal length of silvered lens will be
A
– 10 cm
B
– 20 cm
C
– 40 cm
D
– 80 cm
Answer
– 20 cm
Explanation
Solution
f = 
f = – 20 cm