Question

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

pls answer

Answer 1

Power of lens is the degree to which a lens converges or diverges light.It is reciprocal of Focal length (in metre).

Its SI unit is Dioptre.

Lens of Focal length 40cm will have +ve power and Lens of Focal length -20cm will have -ve power.

HOPE IT'LL HELP

PLSS MARK IT AS. BRAINLIEST

Answer 2

v = 40

$u = - 20 \\ 1 \div 40 - 1 \div - 20 \\ 1 - 2 \div 40 \\ 1 \div 40$

Thus the power of the lens is 1/40

Plzz note the nalture of which lens