Question

What is meant by power of lens? Write its s.i unit A student uses a lens of focal length 40cm and another of -20cm .write the nature and power of each lens?

Answer 1

Power of lens can be defined as reciprocal of focal length...

f= - 20cm
P=100/f = 100/-20 = - 5D

f = 40cm
P=100/f = 100/40 = 2.5D

Hope it helps you dear ☺️☺️

Answer 2

it's a question of yesterday's science paper....power of a lens is defined the converging or diverging power of the lens ....power of lenses are 2.5 and -5 respectively....they are convex and concave lens respectively....hope it helps....please mark as brainliest. :)