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20 (a) Explain two similarities and two differences between the operation of a loudspeaker and the operation of a microphone - OCR Gateway - GCSE Physics - Question 20 - 2023 - Paper 3
Question 20
20 (a) Explain two similarities and two differences between the operation of a loudspeaker and the operation of a microphone. Similarities ------------------------... show full transcript
Worked Solution & Example Answer:20 (a) Explain two similarities and two differences between the operation of a loudspeaker and the operation of a microphone - OCR Gateway - GCSE Physics - Question 20 - 2023 - Paper 3
Step 1
Explain two similarities and two differences between the operation of a loudspeaker and the operation of a microphone.
Answer
Similarities
Both loudspeakers and microphones operate on the principle of electromagnetic induction. When an electric current flows through a coil in a magnetic field, it either generates sound (in the case of a loudspeaker) or produces an electric current in response to sound vibrations (in the case of a microphone).
Differences
- Functionality: A loudspeaker converts electrical energy into sound energy, while a microphone converts sound energy into electrical energy.
- Construction: Loudspeakers usually contain a diaphragm that vibrates to produce sound, whereas microphones have a diaphragm that vibrates in response to sound waves, generating an electrical signal.
Step 2
Describe and explain what happens to the wire when the switch is closed.
Answer
When the switch is closed, an electric current flows through the wire. According to the right-hand rule, a magnetic force is exerted on the wire due to the magnetic field between the North and South poles of the magnet. This results in the wire experiencing a force that is perpendicular to both the direction of the current and the magnetic field, causing it to move. If the current direction is reversed, the direction of the force will also reverse.
Step 3
Calculate the force acting on the wire.
Answer
To calculate the force acting on the wire, we use the formula:
Where:
- is the force,
- is the magnetic flux density (0.30 T),
- is the current (5.0 A),
- is the length of the wire (0.75 m).
Substituting the values:
Rounding to 2 significant figures, the force acting on the wire is 1.1 N.