Question

A student uses a lens of focal length 40 cm and another of minus 20 cm

Answer 1

it means 40cm foacal length lens is concave or converging lens.

while -20cm focal length lens is a convex or diverging lens.

Answer 2

it means 40cm foacal length lens is concave or converging lens.  

while -20cm focal length lens is a convex or diverging lens.

mark me the brainliest