Starter quiz
What is the correct name for the electrical device shown?- an LED bulb
- a filament bulb ✓
- a glass bulb
- a fluorescent bulb
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Why is the filament glowing?- there is a chemical reaction
- the filament is burning
- the vapour in the bulb is glowing
- the wire filament is heated by an electrical current ✓
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- Which of the following statements about filament bulbs is incorrect?
- they are very energy efficient ✓
- they get very hot
- they use a thin wire coil
- they require an electrical current
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- Which of the following statements are correct?
- a voltmeter should be connected in series
- a voltmeter should be connected in parallel ✓
- an ammeter should be connected in series ✓
- an ammeter should be connected in parallel
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Which of the following components is represented by the circuit symbol shown?- resistor
- thermistor
- variable resistor ✓
- fuse
- heater
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- Which of the following equations shows the correct relationship between potential difference, V, current, I and resistance, R?
- R = I × V
- R = I ÷ V
- R = V ÷ I ✓
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Exit quiz
- Match each of the following components to their function in a circuit with a cell and filament lamp.
- voltmeter⇔measures the p.d. across the lamp ✓
- ammeter⇔measures the current through the lamp ✓
- variable resistor⇔changes the p.d. across the lamp ✓
- filament lamp⇔get brighter when more current flows ✓
What mistake has been made in the circuit shown in the diagram below?- only the voltmeter is incorrectly placed
- only the ammmeter is incorrectly placed
- both the voltmeter and ammeter are incorrectly placed ✓
- only the variable resistor is incorrectly placed
- the voltmeter, ammeter and variable resistor are incorrectly placed
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- What is 5 milliamps (mA) when converted to amps (A)?
- 0.005 A ✓
- 0.05 A
- 50 A
- 5000 A
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- A current of 0.6 A flows through a filament lamp when a p.d. of 3.0 V is applied across it. What is the resistance of the lamp in ohms (Ω)?
- 0.2
- 1.8
- 3.6
- 5.0 ✓
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What should the line of best fit look like on the graph shown?- the points should be connected with straight lines between each pair
- a single straight line that doesn't pass through the origin
- a single straight line that passes through the origin
- a single curved line that passes through the origin ✓
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- Which of the following statements are correct when a filament lamp becomes brighter?
- the current has increased ✓
- the current has decreased
- the resistance has increased ✓
- the resistance has decreased
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- An appropriate range of p.d. values includes 0 V and the maximum p.d. of the lamp and at least four other readings.
- For electricity investigations, it is good practice to take many more than the minimum number of measurements.
- After plotting a graph, extra readings could be taken to fill gaps or to check possible errors.
- Plots that lie off the best fit line are possible errors that need to be checked.
- The resistance of a filament lamp is calculated from an I–V graph using pairs of readings and the equation R = V ÷ I.
Common misconception
The terms current, voltage, resistance, energy and power, together with the properties of each, are often mixed up.
As each term is introduced during this lesson, spend a few moments checking pupils’ understanding.
Keywords
Filament lamp - a type of lamp that uses a hot wire to emit light
Variable resistor - a resistor that can be easily changed to any value in its range
Range - the minimum to maximum possible values in an experiment
Repeat reading - when a measurement is taken again to improve the experiment
Best fit line - a line that shows the underlying trend of a set of results on a graph, it can be straight or curved
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