Question

A student uses a lens of focal length 40cm and another of -20 write th nature and power

Answer 1

Given focal length of the lens 1 f₁ = 40 cm = 0.4 m

focal length of the lens 2 f₂ = -20 cm = -0.2 m

Now we know power of lens P = (1/f)

Hence P₁ = (1/f₁) = (1/0.4) =  2.5 D

As power of the lens is positive the nature of lens will be converging.

And P₂ = (1/f₂) = 1/(-0.2) =  -5 D

As power of the lens is negative the nature of lens will be diverging.

Answer 2

Answer:

better ask ur teacher ok