Edexcel IGCSE Physics 2.9 Current-voltage practical
Practise current-voltage investigations by completing circuits, reading I-V graphs and linking graph shape to resistors, lamps and diodes.
- Syllabus
- First assessment 2019
- Course
- Physics 4PH1
Exam points
- place the ammeter in series and the voltmeter in parallel in an I-V circuit diagram
- interpret an I-V graph to distinguish an ohmic resistor from a filament lamp
- draw or extend a best-fit curve when a cell is reversed or voltage changes sign
2.9 Current-voltage practical question 1
[Maximum number: 8]
Question (a)
(a)
A student investigates how current varies with voltage for a metal filament lamp. Draw a diagram of the circuit that a student could use for this investigation.
[ 4 ]
Circuit with symbols for ammeter, voltmeter, lamp and any power supply all correct.
Voltmeter in parallel with lamp.
Ammeter in series with lamp.
Correct means of varying voltage of lamp, e.g. variable power supply / rheostat / potentiometer.
Marking guidance:
- Variable power supplies or variable number of cells can be shown using labelled standard symbols.
- If no lamp in circuit, allow ammeter drawn in series with power supply.
- Allow variable resistor in series with lamp.
Question (b)
(b)
Describe a method the student could use for their investigation.
[ 4 ]
Any four from:
MP1. record ammeter and voltmeter reading
MP2. repeat readings for each voltage and find average
MP3. idea of changing the voltage / current
MP4. plot a graph of voltage and current
MP5. switch off current/circuit between readings
Marking guidance:
- Allow "measure voltage and current".
- Allow a described method that would change voltage or current, e.g. adding more cells or changing circuit resistance.
- Allow repeating experiment to find average.
- Ignore "let lamp cool between readings".
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