Name the two types of spherical mirrors. What type of mirror is represented by the:

1. Back side of a shining steel spoon?
2. Front side of a shining steel spoon?

A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen.

1. In which direction-toward or away from the lens, does he move the screen to focus the image?
2. How does the size of the image change?
3. How does the intensity of the image change as the flame moves towards the lens?
4. Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?

What is the unit of power of a lens? Define the unit of power of a lens.

Light travels more quickly through water than through glass:

1. Which is optically denser: Water or glass?
2. If a ray of light passes from glass into water, which way will it bend: Towards the normal or away from the normal?

Draw a diagram to represent a convex mirror. On this diagram mark principal axis, principal focus F and the centre of curvature C if the focal length of convex mirror is 3cm.

How is the reflection of light ray from a plane mirror different from the refraction of light ray as it enters a block of glass?

List four characteristics of the images formed by plane mirrors.

Explain why, concave mirrors are used as shaving mirrors.

1. How can you bend light away from the normal?
2. How must light travel out of a substance if it is not going to be refracted?

Identify the device used as a spherical mirror or lens in following cases, when the image formed is virtual and erect in each case.
Object is placed between device and its focus, image formed is enlarged and behind it.