Question

A student uses a lens of focal length 60 cm, what is the power of lens?

Answer 1

Explanation:

power of lens =f/2

focal length =60

therefore ,60/2

the power of lens is 30 cm.....

Answer 2

Explanation:

Student A:40cm

p=1/f

p=1/0.4 (40cm=40/100m)

p=1x10/4

p=+2.5D

converging or convex lens.

Student B:f=-20cm

P=1/f

p=1/-0.2(-20cm=-20/100)

p=1x10/-2

p=-5D

diverging or concave lens.