Star constellations

Constellations are small groups of stars which appear in sky in specific shapes. There are about 88 constellations known to us. The names of these constellations have been derived from the names of animals or objects to which they appear to resemble. Some of the...

Galaxies

In the universe, stars are not distributed evenly. Instead these stars clump together to form large clusters called galaxies. Thus, a galaxy is a large group of billions of stars. Galaxies also contain large clouds of hydrogen gas and dust particles. From these gas...

Universe

The vast surrounding space around us which consists of solar system, stars, galaxies, gases and dust particles is called universe. Our universe was formed about fifteen billions years ago by an explosion called Big-Bang. There are approximately 100 billion (1011)...

Combustion of Fuels

 Combustion of Fuels We know that fuels produce energy only when they are burnt in the presence of oxygen. This process of burning of fuels in the presence of oxygen to produce energy is called combustion. The combustion of fuels can take place if following two...

Calorific Value of Fuels

When fuels are burnt, heat is produced. The amount of heat produced by different types of fuels on burning is expressed in terms of calorific value. Calorific value of a fuel may be defined as the amount of heat produced on complete burning of 1 gm of fuel. S.I. unit...