Question

Write a note on power of lens.

Page 46 Chapter - 2.Reflection and Refraction

Answer 1

a convex lens Convergys the light rays falling on it where is a concave lens diverges the light rays falling on it the power of the lens is measure of the degree of the convention and divergence of light rays falling on it if a convex lens converges a beam of a parallel light rays more strongly by focusing them closer to optical Centre it is said to have greater power than the other convex lens which is Focus is the same parallel light rays at a greater distance from optical Centre similarly a concave lens which is divergence parallel beam of a light rays more strongly is said to have a greater diverging power then other concave lens which divergence the light rays less strongly the power of a lens depend on the focal length we can define the power of lens is follows the power of lens is defined as the reciprocal of its focal length in metres