A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its image on the screen.

1. In which direction does he move the lens to focus the flame on the screen?
2. What happens to the size of the image of the flame formed on the screen?
3. What difference is seen in the intensity (brightness) of the image of the flame on the screen?
4. What is seen on the screen when the flame is very close (at about 5 cm) to the lens?

Draw ray diagrams showing the image formation by a convex lens when an object is placed:Between focus and twice the focal length of the lens.

Draw a labelled ray diagram to show how a ray of light is refracted when it passes:

1. From air into an optically denser medium.
2. From an optically denser medium into air.

“The magnification produced by a spherical mirror is - 3”. List four informations you obtain from this statement about the mirror/ image.

Explain how to read the following message which was found on some blotting paper:

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?

Briefly describe how you would find the focal length of a concave mirror quickly but approximately.

The lens A produces a magnification of, -0.6 whereas lens B produces a magnification of +0.6:

1. What is the nature of lens A?
2. What is the nature of lens B?

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray which is directed towards the principal focus of a convex. mirror. Mark on it the angle of incidence and the angle of reflection.

Draw ray diagrams showing the image formation by a concave mirror when an object is placed:A little beyond centre of curvature of the mirror.