Which one of the following is a derived unit?

1. Metre
2. Kelvin
3. Metre³
4. Mole

The S.I. unit of energy is:

1. Joule
2. Kg m²
3. Kg m²s^-3
4. Kg m²s^-1

Which of the following is the smallest unit?

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

What is meant by measurement?