a (1) Define SI unit of power of a lens.
(2)A plano convex lens is made of glass of refractive index 1.5.
The radius of curvature of the convex surface is 25 cm.
(i) Calculate the focal length of the lens.
(ii) If an object is placed 50 cm in front of the lens, find
the nature and position of the image formed.
Solution
1. Power of a lens is defined as the reciprocal of focal-length of the lens. Its SI unit is Dioptre (D), and that is actually reciprocal of 1 meter.
Mathematically
2.
1. Power of a lens is defined as the reciprocal of focal-length of the lens. Its SI unit is Dioptre (D), and that is actually reciprocal of 1 meter.
Mathematically
2.