Question

What is the power of concave lens pf focal length of 25cm ?

Answer 1

f=-25cm As P=100f,f=100-25=-4dioptre. A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it

Answer 2

Answer:

focal length ,f =+25cm = +0.25m

power of a lens is

P = l/f = 1/ +0.25

P = + 4.0 D