Paper 3 Thermal Physics A Drills

Q1 Multi-stage heating

A $0.120\mathrm{kg}$ sample of ice at $-15.0^{\circ }\mathrm{C}$ is heated to water at $25.0^{\circ }\mathrm{C}$. Use $c_{ice}=2100\mathrm{J}\mathrm{k}{\mathrm{g}}^{-1}{\mathrm{K}}^{-1}$, $L_f=3.34\times 10^5\mathrm{J}\mathrm{k}{\mathrm{g}}^{-1}$, and $c_w=4200\mathrm{J}\mathrm{k}{\mathrm{g}}^{-1}{\mathrm{K}}^{-1}$.

1. Identify the three energy stages. [3]
2. Calculate total energy required. [5]
3. Sketch the heating curve qualitatively and label the melting plateau. [2]

Q2 Thermometer calibration

A liquid-in-glass thermometer has liquid-column length $4.0\mathrm{cm}$ at $0^{\circ }\mathrm{C}$ and $24.0\mathrm{cm}$ at $100^{\circ }\mathrm{C}$.

1. Find the temperature when column length is $15.0\mathrm{cm}$ assuming linearity. [3]
2. State two required properties of the thermometric liquid. [2]
3. Explain why calibration is needed. [2]