Physics 9702 · AS & A Level · The first law of thermodynamics

The first law of thermodynamics — practice question

(a)[2]

Two bodies are in thermal equilibrium. State what thermal equilibrium means.

(b(i))[1]

The temperature of a body rises from $15.9\,^{\circ}\text{C}$ to $57.2\,^{\circ}\text{C}$. Determine, in kelvin and to an appropriate number of decimal places, the increase in temperature of the body.

(b(ii))[1]

The temperature of a body rises from $15.9\,^{\circ}\text{C}$ to $57.2\,^{\circ}\text{C}$. Determine, in kelvin and to an appropriate number of decimal places, the final temperature.

(c)[4]

An ideal gas at constant pressure of $1.2 \times 10^{5}\,\text{Pa}$ is heated from $290\,\text{K}$ to a final temperature of $350\,\text{K}$. The gas has a volume increase of $950\,\text{cm}^{3}$. The total change in kinetic energy $\Delta E_{K}$, measured in joules, of the gas molecules is given by $\Delta E_{K} = \frac{3}{2} \times 1.9 \times \Delta T$, where $\Delta T$ is the temperature change in kelvin. Determine the thermal energy needed to produce the temperature change from $290\,\text{K}$ to $350\,\text{K}$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Bodies that share the same temperature

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