Question

Avinash filled a tube with water at $4°C$. The water level was marked as ‘X’. He now cools the water down to $2°C$. What will happen to the water level?​

• A. The water level will be higher than X.
• B. The water level will be lower than X.
• C. The water level will still be at X.
• D. The water level cannot be predicted.

Answer 1

The correct option is A The water level will be higher than X.

The density of a substance decreases with an increase in temperature if the substance expands on heating.
But water is an exception to this. The density of water increases from $0°C\mathrm{to}4°C$ and then decreases when heated above $4°C$.
Therefore, in this case when water is cooled down from $4°C$ to $2°C$, the density of water will decrease and consequently, the volume of water will increase. Hence, the water level will be higher than X.