Question

Assertion: Wise farmers water their fields in the evening if the forecast is severe frost.

Reason: The ice has the highest specific latent heat of fusion.

• A. Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.
• B. Both ‘A’ and ‘R’ are correct, but ‘R’ is not the correct explanation of ‘A’.
• C. ‘A’ is correct, but ‘R’ is incorrect
• D. ‘A’ is incorrect, but ‘R’ is correct

Answer 1

The correct option is A

Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.

The explanation for the assertion:

1. When there is a frost, the water molecules in the air release the latent heat of fusion into the surroundings to convert into the solid form of ice.
2. This process warms up the air after the frost.
3. So farmers need to water their fields in the evening if the forecast is severe frost.

The explanation for the reason:

1. The amount of heat energy required to melt one gram of ice at 0 °C to form water at 0 °C is called the specific heat of fusion of ice.
2. Its value is 336 Jg^-1.

Hence, the correct answer is (A) Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.