Question

1.A convex lens is said to have a real focus and a concave lens a virtual. Why?

2.When does a convex lens form a virtual image?Is the virtual image bigger or smaller than an object?

Answer 1

Hey frnd..... 1)Convex lens bends a parallel beam of light rays to form on to a point at a given distance after refraction of light rays through it on the screen so we say this focus as a real focus, whereas the rays appears to be coming from the focus of the concave lens after refraction of light rays through it, which cannot be obtained on to the screen to form a diminished virtual erect irrespective of the position of the object. So convex lens is said to have a real focus and a concave lens a virtual.

2) If the object is placed between focus and optic centre of the convex lens the enlarged virtual erect image is formed on the same side of the lens as the object. #hope helped

Answer 2

Heya !!

2 ) Virtual and enlarge pic formed ☺