Alternative to Practical: answer from the supplied diagrams and data. Upload drawings or graphs where requested; measurements taken from figures should be shown with their workings.
(a)A student investigates the resistance of a diode at different currents. Fig. 1.1 shows the power source, ammeter, diode, switch, and terminals X and Y. Draw on Fig. 1.1 the symbol for a voltmeter connected to measure the potential difference across the diode.
Answer guidance
Draw Accuracy is being marked. Use the figure and be precise about position and labels.
[1 mark]
(b)With X and Y connected, Fig. 1.2 shows the voltmeter and ammeter readings. Record both readings in the top row of Table 1.1. The table columns are resistance between X and Y / Ω, voltmeter reading V / V, ammeter reading I / A, and resistance of diode R / Ω. The first row has X–Y resistance 0 Ω; its other entries are blank.
[2 marks]
(c)Using the V and I readings in the top row of Table 1.1, calculate the resistance R of the diode with R = V / I. Enter it in the top row to an appropriate number of significant figures.
Answer guidance
Using You must use the thing it names. An answer that reaches the right value another way may not score.
[2 marks]
(d)Complete the two missing values in Table 1.1. The rows (X–Y resistance Ω, V, I, diode R Ω) are (3.3, 0.82, 0.27, 3.0), (6.8, 0.81, blank, 3.7), and (10, 0.81, 0.19, blank). The student connects each resistor between X and Y, records V and I, then removes it.
Answer guidance
Complete Fill in every gap. A partly completed answer usually scores partly.
[2 marks]
(e)(i)Examine Table 1.1 as resistance between X and Y changes. Its printed rows (X–Y resistance / Ω, diode V / V, diode I / A, diode R / Ω) are (0, blank, blank, blank), (3.3, 0.82, 0.27, 3.0), (6.8, 0.81, blank, 3.7), and (10, 0.81, 0.19, blank). Use your earlier completed entries. Describe how the change in current affects voltage across the diode.
Answer guidance
Describe Say what happens, in order. Reasons are not required unless the question also asks why.
[1 mark]
(e)(ii)Examine Table 1.1 as resistance between X and Y changes. Its printed rows (X–Y resistance / Ω, diode V / V, diode I / A, diode R / Ω) are (0, blank, blank, blank), (3.3, 0.82, 0.27, 3.0), (6.8, 0.81, blank, 3.7), and (10, 0.81, 0.19, blank). Use your earlier completed entries. Describe how the change in current affects resistance of the diode.
Answer guidance
Describe Say what happens, in order. Reasons are not required unless the question also asks why.
[1 mark]
(f)A student builds the Fig. 1.1 circuit, connects X and Y and closes the switch. The ammeter does not give a reading, but it is not broken. Suggest an assembly error.
Answer guidance
Suggest More than one answer may be acceptable, so long as it is consistent with the physics.
[1 mark]
5054/42/M/J/24Cambridge O Level Physics 5054 · May/June 2024 · Paper 4 variant 2 · Question 1