Starter quiz
- Which two of the following statements about electricity are correct?
- Metals are good conductors of electricity. ✓
- Plastics are good conductors of electricity.
- Metals are good insulators of electricity.
- Plastics are good insulators of electricity. ✓
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- In a fair test, the variable(s) that need to be kept the same are called ...
- the independent variable.
- the dependent variable.
- control variables. ✓
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Which of the following will happen if another battery is added (correctly aligned and in series) to the circuit shown?- The current will decrease.
- The voltage will stay the same.
- The resistance will increase.
- The number of charge carriers in the wires will stay the same. ✓
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- Which of the following will happen if two identical batteries are connected in series with a lamp, but aligned in opposite directions?
- The lamp won't light. ✓
- The lamp will be brighter.
- The lamp will be the same brightness as it was with one battery.
- The lamp will flicker on and off.
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- Which of the following resistors will oppose the flow of current the most?
- 5 ohm resistor
- 10 ohm resistor
- 15 ohm resistor
- 20 ohm resistor ✓
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- Which of the following will happen if a resistor in a series circuit is moved closer to the battery?
- It will oppose the flow of current more.
- It will oppose the flow of current less.
- The nearer the battery a resistor is, the higher its resistance.
- There will be no effect on its resistance. ✓
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Exit quiz
- Which two of the following statements explain what will happen to a metal atom when it loses an electron?
- It becomes negatively charged.
- It becomes positively charged. ✓
- It stays neutral.
- It becomes an ion. ✓
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- Which two of the following metals are the best conductors of electricity?
- copper ✓
- steel
- nichrome
- silver ✓
- constantan
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- Which of the following statements explain why a thinner metal wire has a higher resistance than a thicker one, per metre?
- It has fewer electrons, per metre, to carry a current. ✓
- It is harder for the electrons to squeeze though the narrow space.
- It has a greater cross–sectional area.
- Making it thinner causes the electrons to stay closer to the atoms.
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The image shown is a representation of the arrangement of the particles in a metal. Which of the following particles do the small, blue spheres represent?- protons
- neutrons
- electrons ✓
- atoms
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- Which of the following statements explain why models are useful when describing electricity?
- They simplify complex ideas. ✓
- They are exactly like the real thing.
- They use examples we are familiar with to help us understand abstract concepts. ✓
- They help us visualise phenomena that we cannot directly observe. ✓
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- Which of the following statements explains what will happen to the resistance and the current carried by a wire if its cross–sectional area is increased?
- Its resistance increases so the current carried also increases.
- Its resistance increases so the current carried decreases.
- Its resistance decreases so the current carried increases. ✓
- Its resistance decreases so the current carried also decreases.
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- The thicker a wire, the smaller its resistance.
- The greater the cross–sectional area of a wire, the smaller its resistance.
- Electric current in a wire is a flow of electrons moving between ‘atoms’ (metal ions).
- Doubling the cross-sectional area of a wire halves its resistance.
- Doubling the cross-sectional area of a wire doubles the number of electrons that can flow through the wire.
Common misconception
Many pupils are likely to still use the terms current, voltage and resistance interchangeably.
Repeatedly question pupils about each term and challenge them to use each one correctly throughout their explanations, both written and verbal.
Keywords
Atom - An atom is the smallest particle of a chemical element that exists.
Electron - Electrons are the charges in conductors that flow to give an electric current.
Metal ion - A metal ion is formed when a metal atom loses one or more electrons and has a positive charge.
Resistance - Resistance is a measure of how hard it is for current to flow.
Proportional - Two variables are proportional if one changes as a multiple of the other.
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