Physics 5054/42 — May/June 2012

Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Experimental Contexts · Analysis, Conclusions and Evaluation · Use of Techniques, Apparatus and Materials · Observations and Measurements · Planning Experiments and Investigations

Q1Use of Techniques, Apparatus and MaterialsExperimental ContextsObservations and MeasurementsAnalysis, Conclusions and EvaluationFree sample

A student investigates the cooling of water.

Some of the apparatus is set up as shown in Fig. 1.1.

Fig. 1.1

A volume of 100 $\text{cm}^3$ of boiling water is poured into the beaker. The student starts the stopclock when the temperature of the water is $90^\circ\text{C}$ .

The water is allowed to cool and its temperature $\theta$ is recorded every 2 minutes.

(a)

(i)

On Fig. 1.1, draw the thermometer in the most suitable position for measuring the temperature of the water as it cools.

(ii)

Suggest a reason why the thermometer should be held in a clamp.

(iii)

Describe how the student avoids parallax error when reading the thermometer.

(b)

(i)

The stopclock measures to the nearest second. Suggest why, in this experiment, the student does not need to use a digital stopwatch measuring to 0.01 s.

(ii)

Explain why the student places the stopclock close to the beaker.

(c)

The student records his results in a table. Fig. 1.2 shows the student’s results.

Fig. 1.2

time $t$ / minutes	$\theta$ / $^\circ\text{C}$
0	90
2	76
4	69
6	65
8	61
10	58
12	55

(i)

On Fig. 1.3, plot the graph of $\theta$ / $^\circ\text{C}$ on the $y$ -axis against $t$ / minutes on the $x$ -axis.
Start your graph from $\theta = 40^\circ\text{C}$ and $t = 0$ .
Draw a curved line of best fit.

Fig. 1.3

(ii)

Explain why the temperature of the water does not fall to $0^\circ\text{C}$ .

(iii)

Use your graph to determine the time taken for the temperature of the water to fall from $90^\circ\text{C}$ to $80^\circ\text{C}$ .

time taken = ______

(d)

The experiment is repeated with the same volume of water in a wider beaker, as shown in Fig. 1.4.

Fig. 1.4

State and explain the effect of using the wider beaker on the time taken for the temperature of the water to fall from $90^\circ\text{C}$ to $80^\circ\text{C}$ .

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3 more questions

Q2Experimental Contexts · Analysis, Conclusions and Evaluation6M
Q3Use of Techniques, Apparatus and Materials · Experimental Contexts · Analysis, Conclusions and Evaluation5M
Q4Experimental Contexts · Observations and Measurements · Analysis, Conclusions and Evaluation · Planning Experiments and Investigations · Use of Techniques, Apparatus and Materials6M

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