Rays from a distant object,incident on a lens A,get focussed on a screen distant 20cm behind the lens.When another lens B is placed midway between the lens A and the screen,the screen had to be moved away by 5cm to refocus the image on the screen .Then,Of the system of lenses used,1)both are convex lenses2)lens A is convex while lens B is concave3)lensB is convex while lens A is concave 4)both are concave lenses

Rankush , 5 Years ago

Grade 11