Why do stars seem higher than they actually are ? Illustrate your answer with the help of a diagram.

(a) How is sound produced? Explain with the help of an example. (b) How does sound from a sound producing body travel through air to reach our ears? Illustrate your answer with the help of a labelled diagram.

"Stars appear higher than they actually are". Give reason.

Why does a driver use a convex mirror instead of a plane mirror as arear view mirror? Illustrate your answer with the help of a ray diagram.

What change is made in the eye to enable it to focus on objects situated at different distances ? Illustrate your answer with the help of diagrams.

Water in a pond appears to be only three-quarter of its actual depth. (a) what property of light is responsible for this observation ? Illustrate your answer with the help of a ray diagram. (b) how is the refractive index of water calculated from its real and apparent depths ?