Explain the formation of Mirage .

Consider the following statements: The principle of total internal reflection is applicable to explain the 1. Formation of mirage in desert. 2. Formation of image in microscope. 3. Colour of evening sky. 4. Operation of optical fibres. Which of the statement given above are correct?

Explain the formation of ozone in the atmosphere.

Explain the formation of chemical bond.

Explain the formation of boron trifluoride.

Explain the formation of a chemical bond.