Question

A body at $110°C$ is dropped into water at $100°C$. What happens to the quantity of water in the container?

• A. remains the same
• B. increases
• C. decreases
• D. the body converts to the liquid state

Answer 1

The correct option is C

decreases

The explanation for the Correct Option:

Option C

1. It is given that water is at $100°C$. And the body is at $110°C$ which is dropped.
2. We know that the boiling point of water is $100°C$
3. And, heat flows from the body at higher temperatures to the body at a lower temperature
4. When a body is dropped into water, it will suddenly transfer the heat to the water, which will ultimately increase the temperature of water above $100°C$
5. And, we know when it happens, Vaporization will occur. Therefore, the quantity of water will decrease as water will change its state to gas.

The explanation for Incorrect Options:

Option A

1. This could be correct if the temperature of the object would be less than that of the temperature of the water.
2. But, this would be incorrect in this case, as the temperature of the object is higher than that of water and evaporation will occur due to the transfer of heat into the water.

Option B

1. It won't be possible, as the quantity of water could never increase if we drop anything into water except water or ice (and let it melt).

Option D

1. There is no possibility for any object to convert to liquid state after being in contact with water at $100°C$
2. As the object is at a higher temperature, it may be in molten form, which can be converted to solid-state, but vice-versa is not possible.

Hence option C is correct.