If the weight of a body in air is W₁, in a liquid is W₂ and in water is W₃, then :

1. R.D. of liquid = $\dfrac{\text{W}$2 - \text{W}3}{\text{W}1 - \text{W}3}

2. R.D. of liquid = $\dfrac{\text{W}$1 - \text{W}2}{\text{W}1 - \text{W}3}

3. R.D. of liquid = $\dfrac{\text{W}$2 - \text{W}3}{\text{W}1 + \text{W}3}

4. R.D. of liquid = $\dfrac{\text{W}$1 - \text{W}2}{\text{W}1 + \text{W}3}

Define the term density.

Express the relationship between the C.G.S. and S.I. units of density.

The density of iron is 7800 kg m^-3. What do you understand by this statement?