A convex lens diverges the rays of light passing through it whereas a concave lens converges the rays of light passing through it.

Why is a convex lens called a convergent lens?

A virtual, diminished image is formed when an object is placed between the optical centre and the principal focus of a lens.
(i) Name the type of lens which forms the above image.
(ii) Draw a ray diagram to show the formation of the image with the above stated characteristics.  

The following diagram shows the use of an optical device to perform an experiment of light.

As per the arrangement shown, the optical device is likely to be a _____.

What are the types of spherical lenses? Describe the principal focus, aperture and the optical centre of a spherical lens.

Complete the ray diagram. Assume P to be a convex lens.

What is meant by the optical centre of a convex lens?