What Is the meaning of cooling Class 11 Physics?

Newton’s Law of Cooling says that the rate at which a body loses heat is directly related to the difference in temperature between the body and its surroundings. This law works best when the temperature difference is small and the way heat is transferred does not change.

This means the heat transfer coefficient—which controls how heat is lost and how temperature changes stays constant. In most materials, thermal conductivity (how easily heat flows through a material) doesn’t change much with temperature, so Newton’s Law works well for heat conduction (as described by Fourier’s Law).

For cooling with fans or flowing liquids (like forced air or pumped water), Newton’s Law generally holds true if the fluid’s properties don’t change much with temperature. However, in natural convection (like warm air rising), the flow speed increases with temperature difference, so the law is only approximately true.

When it comes to heat transfer by radiation, Newton’s Law of Cooling is only accurate for very small temperature differences.