The S.I. unit of pressure is:

1. Kg m^-2s^-2
2. Kg m^-1s^-2
3. Kg m²
4. Kg ms^-2

Which of the following is the smallest unit?

1. Millimetre
2. Angstrom
3. Fermi
4. Metre

What do you understand by the term unit?

How is a physical quantity expressed?