Physics 5054/42 — May/June 2018

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

questions

marks

minutes

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

Q1Experimental ContextsObservations and MeasurementsAnalysis, Conclusions and EvaluationFree sample

A student measures the resistance of a lamp when there are different currents in the lamp.

She sets up the circuit shown in Fig. 1.1.

Fig. 1.1

(a)

On Fig. 1.1, draw the symbol for a voltmeter connected to measure the potential difference $V$ across the lamp.

(b)

She adjusts the variable resistor until she obtains the readings on the voltmeter scale and the ammeter scale shown in Fig. 1.2.

Fig. 1.2

Read, and record in the table of Fig. 1.3, the potential difference $V$ and the current $I$ .

Fig. 1.3

$V / \text{V}$	$I / \text{A}$	$R / \Omega$	brightness of lamp
			bright
0.83	0.11		dim

(c)

The student adjusts the variable resistor and measures the new values of $V$ and $I$ . Her values are shown in the table of Fig. 1.3. The lamp is dimmer.

Use the equation

R = \frac{V}{I}

to calculate the resistance $R$ of the lamp for both settings of the variable resistor.

Record your answers in the table to an appropriate number of significant figures.

(d)

The student thinks that because the same lamp is used throughout the experiment, its resistance is constant.

State whether the student's results confirm this. Justify your answer by referring to the results.

______

(e)

Another student says that the resistance of a lamp filament increases when it gets hot.

State, giving a reason, whether the observations confirm this.

______

The rest of this paper

3 more questions

Q2Experimental Contexts · Observations and Measurements · Use of Techniques, Apparatus and Materials5M
Q3Experimental Contexts · Analysis, Conclusions and Evaluation5M
Q4Observations and Measurements · Experimental Contexts · Analysis, Conclusions and Evaluation14M

Loading the full paper…