Reproduction in Animals — Science STD 8 — Question

A student staying in a coastal region tests the drinking water and also the sea water 'With a circuit in which a part of the connecting wire is wound around a matchbox containing compass. He finds that the compass needle deflects more in the case of sea water. Can you explain the reason?

A wall reflects light and a mirror also reflects light. What difference is there in the way they reflect light?

A beaker contains an acidified copper sulphate solution. A copper plate and a carbon rod are kept in this copper sulphate solution. The copper plate is connected to the positive terminal of a battery whereas the carbon rod is connected to the negative terminal of the battery. What will you observe when an electric current is passed through this set-up for a considerable time?

What are the functions of optic nerve and retina?

Is looking after physical health more important at adolescent age? Give your opinion.

How is the phenomenon of reflection used in making a kaleidoscope. What are the applications of a kaleidoscope?

What is meant by a non-luminous object? Name two non-luminous objects.

Explain the types of friction with examples.

There are two boxes, one made of metal and the other made of wood, which are similar in appearance. How will you find out which box is made of metal?