A convex lens is immersed in a liquid of refractive index greater than that of glass. How will the nature of lens change?

List two possible ways in which a concave mirror can produce a magnified image of an object placed in front of it. State the difference, if any, between these two images.

An object is placed at a distance of 15 cm. from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.

How could you find the focal length of a convex lens rapidly but approximately?

Define and show on a diagram, the following terms relating to a concave mirror:

1. Aperture.
2. Radius of curvature.

An object lies at a distance of 2f from a concave lens of focal length f. Draw a ray-diagram to illustrate the image formation.

A 5cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 18cm at a distance of 12cm from it. Use lens formula to determine the position, size and nature to the image formed.

List some things that concave lens and convex mirror have in common.

Your eye contains a convex lens. Why is it unwise to look at the sun?

List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining image of a distant object on a screen.