Q146 / 180 · COMEDK 2025 (25 May Shift) · Physics
How much heat energy has to be supplied to 2 kg of ice so that it melts at $0^{\circ} \mathrm{C}$ ? [latent heat of fusion of ice is $3.35 \times 10^2 \mathrm{~kJ} \mathrm{Kg}^{-1}$
- A$3.35 \times 10^3 J$
- B$6.7 \times 10^3 \mathrm{~J}$
- C$3.35 \times 10^5 \mathrm{~J}$
- Correct answerD$6.7 \times 10^5 \mathrm{~J}$
Solution
The heat energy $Q$ required to melt a mass $m$ of a substance at its melting point is given by the formula $Q = m \times L$, where $L$ is the latent heat of fusion.
Given:
Mass $m = 2 \text{ kg}$
Latent heat of fusion $L = 3.35 \times 10^2 \text{ kJ kg}^{-1} = 3.35 \times 10^5 \text{ J kg}^{-1}$
Substituting the values into the formula:
$Q = 2 \text{ kg} \times 3.35 \times 10^5 \text{ J kg}^{-1}$
$Q = 6.7 \times 10^5 \text{ J}$
Answer: $6.7 \times 10^5 \mathrm{~J}$
Given:
Mass $m = 2 \text{ kg}$
Latent heat of fusion $L = 3.35 \times 10^2 \text{ kJ kg}^{-1} = 3.35 \times 10^5 \text{ J kg}^{-1}$
Substituting the values into the formula:
$Q = 2 \text{ kg} \times 3.35 \times 10^5 \text{ J kg}^{-1}$
$Q = 6.7 \times 10^5 \text{ J}$
Answer: $6.7 \times 10^5 \mathrm{~J}$
Hence, the correct answer is option: 'D'.