Questions

Q1.   A student connected the circuit shown. The battery has negligible internal resistance.

The graph shows how the resistance of the thermistor varies with temperature.

(a)  The reading on the voltmeter is 3.42 V.
Determine the temperature of the thermistor.
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Temperature = ........................................................... 
(b)  The student suggests that if the e.m.f. of the battery is doubled, the reading on the voltmeter will double. Assess whether the student's suggestion is correct.
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 (Total for question = 8 marks) (Q14 WPH12/01, June 2021) 

Q2. A student investigated the internal resistance of a cell, using the circuit shown.

The student used the variable resistor to vary the reading on the ammeter. He recorded corresponding readings from the voltmeter.
The student plotted the results on a graph, as shown.

(a)  Determine the e.m.f.  ε of the cell, and the internal resistance r of the cell.
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 ε = ........................................................... 
r = ........................................................... 

Q3. A student carried out an experiment to determine the e.m.f. ε and internal resistance r of 
a potato cell. The potato used in the experiment was connected to the rest of the circuit 
using electrodes of two different metals as shown.

(a)  Complete the diagram below to show a circuit that could be used in order to
determine ε and r for the potato cell.
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(b)  The student completed the experiment and plotted a graph showing the relationship
between potential difference V and current I as shown.

Use the graph to determine values for ε and r.
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ε = ........................................................... 
r = ........................................................... 
(c)  In a separate experiment two resistors, with equal resistance R, are connected
to a battery (with internal resistance r) with the two resistors firstly in a series 
arrangement (diagram A) and then in a parallel arrangement (diagram B).

Explain which, if either, of the two arrangements would lead to a greater value for the 
terminal potential difference.
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 (Q19 WPH12/01, June 2019) 

Q4. Four identical resistors, A, B, C and D, are placed in a circuit as shown.

(a)  Determine the power dissipated in each of the resistors.
resistance of each resistor = 2.0 Ω

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(b)  Explain, without further calculation, what would happen to the power dissipated by resistor A if resistor D were disconnected from the circuit.
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(c)  If the resistors in the circuit used in (a) were replaced with filament lamps, the resistance of each lamp would be different depending on the potential difference across it.
Explain, in terms of particles, why the resistance of a filament lamp increases as the potential difference across the filament increases.
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 (Q18 WPH12/01, Oct 2020) 

Q5.  A student is given the circuit diagram shown.

(a)  Calculate a value for the voltmeter reading.
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Voltmeter reading = ........................................................... 

(b)  The student sets up the circuit and observes that the reading on the voltmeter is lower than the value calculated in (a).
Explain two reasons for the lower voltmeter reading.
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(Total for question = 6 marks)

(Q12 WPH12/01, Oct 2020) 

Mark Scheme

Q1.

 

Q2.

 

Q3.

 

Q4.

 

Q5.