Carbon and its Compounds — Science STD 10 — Question

Explain why, concave mirrors are used as shaving mirrors.

An element X is in group 2 of the periodic table:

1. What will be the formula of its chloride?
2. What will be the formula of its oxide?

Why are forests considered "biodiversity hot spots"? List two ways in which an individual can contribute effectively to the management of forests and wildlife.

Give the names and structural formulae of the next two higher homologues of methane.

State two ways in which the energy of sea-waves can be harnessed.

What is an electric current? What makes an electric current flow in a wire?

1. Distinguish between renewable and non-renewable sources of energy.
2. Choose the renewable sources of energy from the following list: Coal, biogas, sun, natural gas.

Calculate the number of electrons constituting one coulomb of charge.

When a person breathes in air, the air enters into his body through an organ Ahaving two holes B in it. The air then passes through pharynx and larynx and enters into a tube C. The tube C divides into two smaller tubes D at its lower end. The two smaller tubes are attached to two respiratory organs E. Each smaller tube divides inside the organs E to form a large number of still smaller tubes called F. The smallest tubes F have air-sacs G at their ends in which gaseous exchange takes place in the body of the person. What are A, B, C, D, E, F and G?

Write one use of wind energy.

1. In the past.
2. At present.