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8.1 Define electromagnetic induction - NSC Technical Sciences - Question 8 - 2020 - Paper 1
Question 8
8.1 Define electromagnetic induction. 8.2 Name TWO factors that influence the induced emf. 8.3 State Lenz's law in words. 8.4 Give THREE examples where Lenz's law... show full transcript
Worked Solution & Example Answer:8.1 Define electromagnetic induction - NSC Technical Sciences - Question 8 - 2020 - Paper 1
Step 1
Define electromagnetic induction.
Answer
Electromagnetic induction is the process by which a change in magnetic field within a closed loop of wire induces an electromotive force (emf) in the wire. This occurs due to Faraday's law of electromagnetic induction, which states that the induced emf is directly proportional to the rate of change of the magnetic flux through the loop.
Step 2
Name TWO factors that influence the induced emf.
Answer
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The rate of change of the magnetic field: A faster change in magnetic flux results in a greater induced emf.
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The number of turns in the coil: Increasing the number of turns in the coil increases the induced emf, as each loop contributes to the total flux change.
Step 3
State Lenz's law in words.
Answer
Lenz's law states that the direction of the induced electromotive force (emf) and the resulting current in a closed loop will be such that it opposes the change in magnetic flux that produced it. This means the induced current generates a magnetic field that counteracts the original change.
Step 4
Give THREE examples where Lenz's law is applied.
Answer
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When a magnet is moved towards a conducting loop, the induced current flows in a direction that creates a magnetic field opposing the magnet's motion.
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In electromagnetic braking systems of trains, Lenz’s law explains how induced currents in the rails oppose the motion of the train, providing a braking force.
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In electric generators, Lenz's law dictates that as the generator spins, the induced current flows in a manner that opposes the mechanical input used to turn the generator.