The radius of curvature of a concave mirror is 50cm. Where should an object be placed in the mirror, so as to form its image at infinity? Justify your answer.

Define power of a lens. What is its unit? One student uses a lens of focal length 50cm and another of -50cm. What is the nature of the lens and its power used by each of them?

Describe an activity to show that the colours of white light splinted by a glass prism can be recombined to get white light by another identical glass prism. AIso draw ray diagram to show the recombination of the spectrum of white light.

An object 4cm high is placed at a distance of 10cm from a convex lens of focal length 20cm. Find the position, nature and size of the image.

A convex lens has a focal length of 10cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20cm away from the lens? What would be the size of the image formed if the object is 2cm high? With the help of a ray diagram show the formation of the image by the lens in this case.

What is meant by the ‘angle of incidence’ and the ‘angle of refraction’ for a ray of light? Draw a labelled ray diagram to show the angle of incidence and the angle of refraction for a refracted ray of light.

Giving reasons, state the ‘signs’ (positive or negative) which can be given to the following:

1. Object distance (u) for a concave mirror or convex mirror.
2. Image distances (v) for a concave mirror.
3. Image distances (v) for a convex mirror.

State and explain the New Cartesian Sign Convention for spherical lenses.

A small object is so placed in front of a convex lens of 5cm focal length that a virtual image is formed at a distance of 25cm. Find the magnification

Name the type of mirror used in the following situations.

1. Headlights of a car.
2. Side/rear-view mirror of a vehicle.
3. Solar furnace.

Support your answer with reason.