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Calorimetry

Practice Questions:

Question 21: easy

Assertion (A): A bottle is filled with water at $40^{\circ}\text{C}\text{ on opening it at moon, water will boil}$.

Reason (R): Atmospheric pressure on the surface of moon is zero and boiling point is proportional to pressure.

1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)

2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

3. (A) is true but (R) is false

4. Both (A) and (R) are false

View Answer

The moon has a negligible atmosphere, leading to near-zero surface pressure. At such low pressures, water's boiling point decreases significantly. Consequently, water at $40^{\circ}\text{C}\text{ would readily boil}$. Both (A) and (R) are true, and (R) provides the correct explanation for (A).

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Question 22: easy

Water equivalent of a metallic bar is $100\text{ g}$, the energy required to increase its temperature by $1^\circ\text{C}$ is

1. 100 cal

2. 1000 cal

3. 500 cal

4. 50 cal

View Answer

Energy required is $Q = w \cdot \Delta T$, where $w$ is the water equivalent. Thus, $Q = 100\text{ g} \times 1\text{ cal/g}^\circ\text{C} \times 1^\circ\text{C} = 100\text{ cal}$.

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