Loudspeakers & Microphones
Loudspeakers and microphones are devices that convert between sound waves and electrical signals. A loudspeaker uses the motor effect to turn an electrical signal into sound. A varying current in a coil attached to a cone causes it to vibrate, creating sound waves. A microphone does the opposite, using the generator effect. Sound waves make a diaphragm and a coil vibrate in a magnetic field, which induces a current that matches the sound.
Full topic guide: the detailed syllabus page with worked examples and common mistakes lives at studyvector.co.uk/gcse/physics/magnetism-electromagnetism/loudspeakers-microphones.
Topic preview: Loudspeakers & Microphones
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Topic explanation
Loudspeakers and microphones are devices that convert between sound waves and electrical signals. A loudspeaker uses the motor effect to turn an electrical signal into sound. A varying current in a coil attached to a cone causes it to vibrate, creating sound waves. A microphone does the opposite, using the generator effect. Sound waves make a diaphragm and a coil vibrate in a magnetic field, which induces a current that matches the sound.
Loudspeakers & Microphones is easiest to revise when it is treated as a precise exam behaviour, not a loose note-taking category. In GCSE Physics, the goal is to recognise how the topic appears in a question, identify the command word, and decide what evidence, method, or vocabulary earns marks. StudyVector keeps this page tied to AQA · Edexcel · OCR language where coverage is available, then routes practice towards the same topic so revision moves from explanation into retrieval.
A strong revision session starts with a short recall check. Write down the rule, definition, process, or method linked to Loudspeakers & Microphones before looking at any notes. Then answer one exam-style prompt and compare your answer with the mark-scheme logic: did you make a clear point, support it with the right step, and avoid drifting into a nearby topic? This matters because many lost marks come from almost-correct answers that do not match the expected structure.
Use this guide as the first layer: understand the topic, look at the worked examples, complete the mini quiz, then move into full practice. The full StudyVector practice loop is designed to capture whether mistakes are caused by knowledge, method, language, or timing. That distinction is important. If the error is factual, you need reteaching. If the error is method-based, you need a worked retry. If the error is wording, you need command-word calibration. That is how Loudspeakers & Microphones becomes a controlled revision target rather than another page in a folder.
Lost marks → repair task
Why marks are usually lost here
These are the error patterns StudyVector looks for after an attempt. The goal is not a generic explanation; it is one repair move and one follow-up question.
Unit, formula, or method slip
Examiner move: Select the correct method and keep units, substitutions, signs, and rounding visible.
Repair drill: Redo the calculation or method line slowly, naming the formula before substituting values.
Missing chain of reasoning
Examiner move: Show the link between point, method, evidence, and conclusion instead of jumping to the final line.
Repair drill: Write the missing because/therefore step, then retry one isomorphic question.
Weak evidence or data reference
Examiner move: Use a precise value, quote, example, diagram feature, or syllabus term to support the claim.
Repair drill: Add one concrete reference to the answer and remove any generic sentence that does not earn a mark.
Mini quiz
Use these checks before full practice. They test topic recognition, exam technique, and whether you can connect the explanation to a marked response.
1. What should you check first when a Loudspeakers & Microphones question appears in GCSE Physics?
- A.The command word and the exact topic focus
- B.The longest paragraph in your notes
- C.A memorised answer from a different topic
2. Which revision action gives the strongest evidence that Loudspeakers & Microphones is improving?
- A.Rereading the explanation twice
- B.Answering a timed exam-style question and reviewing lost marks
- C.Highlighting every key phrase in the topic notes
Sample questions
Topic-specific public question previews are still being reviewed. We keep them off public pages until the topic match is safe.
Exam tips
- Read the command word carefully — "explain" needs reasons; "state" expects a short fact.
- For Loudspeakers & Microphones, show structured working even when you are practising multiple choice — it builds accuracy under time pressure.
- Mark yourself against the mark scheme style: one clear point per mark, in logical order.
- Come back to this topic after a day or two; short spaced reviews beat one long cram.
Worked examples
Example 1
Modelled exam response
Explain how a loudspeaker creates a sound wave. Solution: An alternating electrical signal is passed through a coil of wire attached to a cone. The coil is in a magnetic field, so it experiences a force due to the motor effect. As the current changes direction, the force changes direction, causing the coil and the cone to vibrate. These vibrations push and pull on the air, creating sound waves.
Example 2
Identify the task before answering
Question type: a Loudspeakers & Microphones prompt asks for a clear response in GCSE Physics. Step 1: underline the command word. Step 2: name the exact part of Loudspeakers & Microphones being tested. Step 3: decide whether the mark scheme wants a definition, method, explanation, comparison, or calculation. Why it works: most weak answers fail before the content starts because they answer the topic generally rather than the exact exam task.
Example 3
Turn feedback into a repair task
Suppose your answer shows partial understanding but loses marks for precision. First, rewrite the missing mark as a short target: "I need to state the mechanism, unit, reason, or evidence explicitly." Then answer one similar question without notes. Finally, compare the second attempt with the first and check whether the same mark was recovered. Why it works: Loudspeakers & Microphones improves faster when feedback creates a specific retry, not another passive reading session.
Next revision routes from this subject
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Common mistakes
- Confusing which device uses which effect. Loudspeaker = Motor Effect (electrical to sound). Microphone = Generator Effect (sound to electrical).
- Not being able to explain how the vibrations are created or detected. It is all about the interaction between the coil, the magnet, and the cone/diaphragm.
- Thinking that the current in a loudspeaker is constant. It must be a varying alternating current that matches the frequency of the desired sound.
Exam board notes
Covered by AQA and Edexcel. OCR covers the principles but may not focus on these specific devices in as much detail. The link to the motor and generator effects is key.
FAQs
How does a microphone work?
In a dynamic microphone, sound waves cause a diaphragm to vibrate. A coil attached to the diaphragm also vibrates within a magnetic field. This movement of the coil in the field induces an electrical current that mirrors the original sound wave.
What is the difference between a loudspeaker and a microphone?
A loudspeaker converts electrical energy into sound energy. A microphone converts sound energy into electrical energy. They are essentially the reverse of each other.
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