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. The nature and power of the each lens

Answer 1

Answer:

power of lens means focal length of a lens

Explanation:

we know that

1/f=1/v-1/u

1/40=1/v-1/-20

sorry

Answer 2

Answer:

F1=40,

Explanation:

p=1/F1

p=100/40

p=2.5D

F2=20c.m

p2.=100/20

p2=5D

/f1=100/40