Question

In which of the following cases evaporation of water will be the slowest?

• A. A tray of water kept in sunlight.
• B. A kettle of water kept on a burner.
• C. A glass of water kept in a room.
• D. A bucket of water kept on rooftop.

Answer 1

The correct option is C

A glass of water kept in a room.

Explanation for correct option:

Option (c) A glass of water kept in a room.

• The temperature has a direct relationship with evaporation.
• That is why, when the temperature rises, so does evaporation.
• The temperature in the room will be lower than that of the burner, the roof, or the sun.
• As a result, at room temperature, evaporation will be slower.
• When a liquid substance evaporates, it changes into a gas.
• The molecules move and vibrate so swiftly that they disperse as water vapour molecules into the atmosphere.

Explanation for incorrect options:

Option (a) A tray of water kept in sunlight.

• A tray provides a larger surface area for evaporation to act
• So, the water from the tray evaporates really fast because evaporation is directly proportional to the surface area.
• So, this option is incorrect.

Option (b) A kettle of water kept on a burner.

• Water evaporates when it becomes heated.
• When a kettle full of water is kept on the burner, the water evaporates very fast.
• So, this option is incorrect.

Option (d) A bucket of water kept on rooftop.

• Due to the direct exposure to sunlight, the water in the bucket evaporates.
• It is converted to a gaseous form due to the temperature rise at a very fast rate.
• So, this option is also incorrect.

Hence, the correct option is (c) A glass of water kept in a room.