Stars and the solar system. — Science STD 8 — Question

Give two examples from everyday life which show that air exerts pressure.

Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room? Explain.

What change in the voice of body takes place when they reach puberty? What is the cause of this change?

Where do Rhizobium bacteria live? What is their function?

An incident ray makes an angle of 75° with the surface of a plane mirror. What will be the angle of reflection?

Which of the following are kharif crops and which are rabi crops?
Wheat, Paddy, Gram, Maize, Mustard, Cotton, Soyabean, Linseed, Peas, Groundnut.

Name an instrument or toy which works by producing multiple reflections from three plane mirrors to form beautiful patterns.

What is menstruation? Explain.

Which planet is known as the red planet?

What is a polymer? Name the natural polymer of which cotton is made.