Paper 4 Thermal Physics Route Drills

Q1 Selecting a thermal experiment

A student must determine a specific heat capacity electrically.

1. State the measurements needed. [3]
2. State why insulation is used. [1]
3. Explain how heat loss affects the calculated value if ignored. [2]

Q2 Gas-law graph

A constant-volume gas thermometer records the following pressures at different Celsius temperatures.

$\theta /{}^{\circ }\mathrm{C}$	$p/\mathrm{kPa}$
-20	101.3
10	113.1
40	125.4
70	137.2
100	149.4

1. Plot $p$ against $\theta$ and draw a best-fit straight line. [5]

2. Extrapolate the line to estimate absolute zero. [3]
3. Explain why the estimate has greater uncertainty than temperatures within the measured range. [2]
4. State one physical limitation of interpreting the extrapolation as the behaviour of a real gas down to that temperature. [1]