What is meant by noise pollution? Name one source of sound causing noise pollution.

A ray of light falls normally on a rectangular glass slab. Draw a ray diagram showing the path of the ray till it emerges out of the slab.

Read the extract given below and answer the questions that follow:

It had no eyes, ears, nose or mouth. It was just a round smooth head - with a school cap on top of it! And that’s where the story should...

The particles present in strong electrolytes are:

1. only molecules
2. mainly ions                                                                                                                                                                         
3. ions and molecules
4. only atoms.

Name the soil which: occurs exsitu

Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

The process by which sulphide ore is concentrated.

State what would you observe when:

1. Washing Soda Crystals are exposed to the atmosphere.
2. The salt ferric chloride is exposed to the atmosphere.

Give a reason: Water transport is not as popular as land transport in India

Gyri and Sulci are the folds of Cerebellum.

Rewrite the correct statement by changing the underlined words.

Arrange α, β and γ rays in ascending order with respect to their

1. Penetrating power.
2. Ionising power.
3. Biological effect

The first and last term of a Geometrical Progression (G.P.) are 3 and 96 respectively. If the common ratio is 2, find:

1. ‘n’ the number of terms of the G.P.
2. Sum of the n terms.

Baeyer's process is used to concentrate bauxite ore to alumina.

Give balanced chemical equations for the reaction taking place for its conversion from bauxite to alumina.

State one relevant observation: Addition of excess ammonium hydroxide into copper sulphate solution.

What happens to the level of water when this setup is placed in

1. Humid conditions?
2. Windy conditions?

Na, K, Li (Increasing atomic size)