Describe with the help of a ray diagram the nature, size and position of the image formed when an object is placed in front of a convex lens between focus and optical centre. State three characteristics of the image formed.

What is the difference between regular reflection of light and diffuse reflection of light? What type of reflection of light takes place from:

1. A cinema screen.
2. A plane mirror.
3. A cardboard.
4. Still water surface of a lake

Draw the ray diagram and also state the position, relative size and nature of the image formed by a concave mirror when the object is placed between its centre of curvature, C and the focus, F.

Which mirror is used as a torch reflector? Draw a labelled diagram to show how a torch reflector can be used to produce a parallel beam of light. Where is the bulb placed in relation to the torch reflector?

An object of height 4.25mm is placed at a distance of 10cm from a convex lens of power +5D. Find:

1. Focal length of the lens, and
2. Size of the image.

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 25 cm, where is the object placed? Find the nature and focal length of the lens. If the object is displaced 15 cm towards the optical centre of the lens, where would the image be formed? Draw a ray diagram to justify your answer.

State where an object must be placed so that the image formed by a concave mirror is:

1. Erect and virtual.
2. At infinity.
3. The same size as the object.

How is the refractive index of a medium related to the speed of light? Obtain an expression for refractive index of a medium with respect to another in terms of speed of light in these two media?