ICSE Class 9 Answered

The amount of solar energy which is received by the Sun is known as insolation. The Sun’s energy reaches the Earth as short waves. Out of total solar energy, 51% reaches the Earth. The Earth does not absorb all the heat of the Sun which strikes its surface. A part of Sun’s heat is radiated back into the atmosphere in form of long waves. The heat radiated by the earth in form of long waves is known as terrestrial radiation. The balance maintained between the incoming solar radiation absorbed by the earth and the heat that escapes from the Earth into the space is known as the heat budget. Following is an example of the heat budget of the earth: