Paper 4 Thermal Physics A Drills

Q1 Electrical heating practical

A student supplies constant electrical power $P=18.0\mathrm{W}$ to an insulated metal block of mass $0.480\mathrm{kg}$. The measured temperatures are:

$t/\mathrm{s}$	0	60	120	180	240	300
$\theta /{}^{\circ }\mathrm{C}$	21.0	23.5	26.1	28.5	31.1	33.5

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

2. Use the gradient to determine the apparent specific heat capacity of the block. [3]
3. Explain why ignoring heat loss makes this apparent value larger than the true specific heat capacity. [2]
4. State two ways to reduce heat loss. [2]
5. Explain why the thermometer should be close to the heater but not touching it. [2]

Q2 Latent heat practical

A heater is used to boil water and determine $L_v$.

1. State the measurements needed. [3]
2. Explain why a correction for evaporation before timing may be needed. [2]
3. State one safety precaution. [1]