9. Images formed due to refraction through a convex and concave lens

When an object is placed in front of a lens, the object's light rays strike the lens. The position, size, and nature of the formed image can only be understood if certain basic rules are followed.

 

Rule-1:

 

When a ray of light strikes the convex or concave lens obliquely at its optical centre, it continues to follow its path without any deviation.

 

 

Rule-2:

 

When rays parallel to the principal axis strikes a convex or concave lens, the refracted rays are converged to (convex lens) or appear to diverge from (concave lens) the principal focus.

 

 

Rule-3:

 

When a ray passing through (convex lens) or directed towards (concave lens), the principal focus strikes a convex or concave lens, the refracted ray will be parallel to the principal axis.