Physics 5054 · O Level · Transfer of thermal energy
Transfer of thermal energy — practice question
A student is studying how fitting a lid changes the rate at which hot water in a beaker cools.
• She transfers $200\,\text{cm}^3$ of hot water into a beaker.
• She puts a thermometer into the water, as shown in Fig. 4.1.
• She leaves it for a brief period.
• She notes the water temperature and, at the same moment, starts a stopwatch.
This is at time $t = 0$.
Fig. 4.2 shows the thermometer at time $t = 0$.
(a(i))[1]
Write down the temperature $\theta$ indicated by the thermometer at time $t = 0$.
(a(ii))[1]
State why the student leaves a short delay before taking the thermometer reading at time $t = 0$.
(b)[1]
Explain how the values in Table 4.1 demonstrate that the water cools faster when no lid is used.
(c)[1]
Name one quantity that the student has to keep unchanged to compare fairly the speeds of cooling of the two beakers.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “83.0 ^{\circ}C ” …