Question

A student uses a lens of focal length -30 cm. What is the power and nature of this lens?

Answer 1

Power of lens = 1/focal length (in metres)

Convert 30cm into metres

1cm=1/100 m

30cm = 30/100 m

Put value in formula

Power = 1/-30/100

Power = -100/30

=-10/3 Dioptre

Nature- diverging lens or concave lens

Answer 2

Answer:

One student uses a lens of focal length 50cm and another of -25cm. What is the nature

of lens and its power used by each of them?