Quick answer: Current is the flow of charge in amperes, potential difference is the energy per coulomb in volts, and resistance in ohms is the opposition to current. This Physics 9-10 test on ohm's law has 8 questions worth 20 marks, to do in 45 minutes: definitions, using V = I R and measuring resistance. The mark scheme is on a separate page; free printable PDF.
this test covers V = I R, circuit measurements, I-V graphs and sensors. Firstly, show your working and give units. You may also use a calculator and a ruler, because the paper is worth 20 marks.
Level: Physics grades 9-10 (GCSE · IGCSE · O Level · Class 9-10) · Curriculum: GCSE P2, IGCSE 4.3
Question 1 Definitions (2 marks)
- Firstly, write the equation that defines resistance. (1 mark)
- Then state what a potential difference of 1 volt means. (1 mark)
Question 2 Using V = I R (3 marks)
- A resistor has 7.5 V across it and a current of 0.050 A, so calculate its resistance. (2 marks)
- Then calculate the potential difference when you raise the current to 0.080 A. (1 mark)
Question 3 Measuring resistance (3 marks)
The circuit shows a cell and a resistor R, but no meters.
- Firstly, copy the circuit and add an ammeter and a voltmeter to measure the resistance of R. (2 marks)
- Finally, state the equation you use to find R. (1 mark)
Question 4 Filament lamp (3 marks)
In addition, the I-V graph of a filament lamp is a curve whose gradient decreases as the voltage increases. Also, explain what this shows about the resistance and why it happens. (3 marks)
Question 5 Sensors (3 marks)
- Firstly, state how the resistance of an LDR changes when the light intensity increases. (1 mark)
- After that, describe how a thermistor can switch on a cooling fan. (2 marks)
Question 6 Energy transferred (2 marks)
A charge of 25 C passes through a lamp when the potential difference across it is 12 V. Then calculate the energy transferred. (2 marks)
Question 7 Diode (2 marks)
Firstly, state what a diode does to a current, and then give one use. (2 marks)
Question 8 Longer wire (2 marks)
Then a wire has a resistance of 6.0 Ω. Another wire of the same material and thickness is twice as long, so state its resistance and explain. (2 marks)
