An object is placed at a distance of 100cm from each of the above lenses A and Calculate:

1. Image distance, and
2. Magnification, in each of the two cases.

At what distance should an object be placed from a convex lens of focal length 18cm to obtain an image at 24cm from it on the other side? What will be the magnification produced in this case?

A concave mirror has a focal length of 4cm and an object 2cm tall is placed 9cm away from it. Find the nature, position and size of the image formed.

Explain with the help of a labelled ray diagram, why a pencil partly immersed in water appears to be bent at the water surface. State whether the bending of pencil will increase or decrease if water is replaced by another liquid which is optically more dense than water. Give reason for your answer.

State the type of mirror preferred as,

1. Rear view mirror in vehicles.
2. Shaving mirror. Justify your answer giving two reasons in each case.

A ray of light enters a diamond from air. If the refractive index of diamond is 2.42, what % (percentage) is speed of light in diamond with that of speed in air?

A lens of focal length 20cm is used to produce a ten times magnified image of a film slide on a screen. How far must the slide be placed from the lens ?

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.

The magnification of an image formed by a lens is – 1. If the distance of the image from the optical centre of the lens is 35 cm, where is the object placed ? What is the nature and focal length of the lens? If the object is displaced 20 cm towards the optical centre of the lens, where would the image be formed and what will be its nature? Draw a ray diagram to justify your answer.

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.