# GCSE Standard Questions: Electric Circuits

Q14.

(a) Chloe investigated how the current in resistor R varied box with the potential difference across the resistor. She maintained a constant temperature for the resistor throughout the experiment.

She recorded both positive and negative values of current in her notebook.

Here is the circuit Chloe used:

Describe a method that Chloe could have used for this investigation.

[6 marks]

(b) Lois repeated the investigation.

During Lois's investigation the temperature of resistor R increased.

Explain how the increased temperature of resistor R would have affected Lois's results.

[2 marks]

(c) The diagram shows the scale on the analogue moving coil ammeter Chloe used, at one time in the investigation.

(i) What is the resolution of the moving coil ammeter?

(ii) What value of the current is shown by the meter?

[2 marks]

(d) Lois replaced the moving coil ammeter with a digital ammeter.

The diagram shows a reading on the digital ammeter.

The digital ammeter has a higher resolution than the moving coil ammeter.

(i) What is the resolution on the digital ammeter?

(ii) Give a reason other than resolution why it would have been better to use the digital ammeter throughout this investigation.

[2 marks]

(Total 12 marks)