Power of a Lens

a) What do you understand by the power of a lens? Name one factor on which the power of a lens depends. b) What is the unit of power of a lens? Define the unit of power of a lens. c) A combination of lenses for a camera two converging lenses of focal length 20 cm and 40 cm and a diverging lens of focal length 50 cm. Find the power and focal length of the combination.

Assertion:A convex lens and a concave lens are kept in contact. They will behave as a diverging lens if focal length of convex lens is more. Reason: Power of a concave lens is always less than the power of a convex lens, as power of concave lens is negative whereas power of convex lens is positive.

Thin lens (Part-2)|Power of lens| combination of lens| silvered lens

Power Of Lens

Power of the lens is the ___________ of the focal length .

If the focal length of a magnifler is 5cm calculate a) the power of the lens b) the magnifying power of the lens for relaxed and strained eye.

If for a lens, F=-20 cm, what is the power of the lens ?