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11.1 – Electromagnetic induction
Description
Nature of science:
Experimentation: In 1831 Michael Faraday, using primitive equipment, observed a minute pulse of current in one coil of wire only when the current in a second coil of wire was switched on or off but nothing while a constant current was established. Faraday’s observation of these small transient currents led him to perform experiments that led to his law of electromagnetic induction. (1.8)
Understandings:
- Emf
- Magnetic flux and magnetic flux linkage
- Faraday’s law of induction
- Lenz’s law
Applications and skills:
- Describing the production of an induced emf by a changing magnetic flux and within a uniform magnetic field
- Solving problems involving magnetic flux, magnetic flux linkage and Faraday’s law
- Explaining Lenz’s law through the conservation of energy
Guidance:
- Quantitative treatments will be expected for straight conductors moving at right angles to magnetic fields and rectangular coils moving in and out of fields and rotating in fields
- Qualitative treatments only will be expected for fixed coils in a changing magnetic field and ac generators
Data booklet reference:
Theory of knowledge:
- Terminology used in electromagnetic field theory is extensive and can confuse people who are not directly involved. What effect can lack of clarity in terminology have on communicating scientific concepts to the public?
Utilization:
- Applications of electromagnetic induction can be found in many places including transformers, electromagnetic braking, geophones used in seismology, and metal detectors
Aims:
- Aim 2: the simple principles of electromagnetic induction are a powerful aspect of the physicist’s or technologist’s armoury when designing systems that transfer energy from one form to another.
Directly related questions
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17N.1.HL.TZ0.34:
The plane of a coil is positioned at right angles to a magnetic field of flux density B. The coil has N turns, each of area A. The coil is rotated through 180˚ in time t.
What is the magnitude of the induced emf?
A.
B.
C.
D.
-
17N.1.HL.TZ0.34:
The plane of a coil is positioned at right angles to a magnetic field of flux density B. The coil has N turns, each of area A. The coil is rotated through 180˚ in time t.
What is the magnitude of the induced emf?
A.
B.
C.
D.
- 17N.2.HL.TZ0.2e: The magnetic field strength of the Earth is 31 μT at the orbital radius of the satellites. The...
- 17N.2.HL.TZ0.2c: The cable between the satellites cuts the magnetic field lines of the Earth at right...
- 17N.2.HL.TZ0.2e: The magnetic field strength of the Earth is 31 μT at the orbital radius of the satellites. The...
- 17N.2.HL.TZ0.e: The magnetic field strength of the Earth is 31 μT at the orbital radius of the satellites. The...
- 17N.2.HL.TZ0.2c: The cable between the satellites cuts the magnetic field lines of the Earth at right...
- 17N.2.HL.TZ0.c: The cable between the satellites cuts the magnetic field lines of the Earth at right...
- 18M.1.HL.TZ1.33: Two identical circular coils are placed one below the other so that their planes are both...
- 18M.1.HL.TZ1.33: Two identical circular coils are placed one below the other so that their planes are both...
- 18M.1.HL.TZ2.33: The current I flowing in loop A in a clockwise direction is increasing so as to induce a...
- 19M.2.HL.TZ2.10a: While the magnet is moving towards the ring, state why the magnetic flux in the ring is increasing.
- 18M.1.HL.TZ2.33: The current I flowing in loop A in a clockwise direction is increasing so as to induce a...
- 18M.1.HL.TZ2.34: A rectangular flat coil moves at constant speed through a uniform magnetic field. The direction...
- 18M.1.HL.TZ2.34: A rectangular flat coil moves at constant speed through a uniform magnetic field. The direction...
-
19M.1.HL.TZ1.35:
The graph below shows the variation with time of the magnetic flux through a coil.
Which of the following gives three times for which the magnitude of the induced emf is a maximum?
A. 0, ,
B. 0, , T
C. 0, , T
D. , ,
-
18N.1.HL.TZ0.33:
A ring of area S is in a uniform magnetic field X. Initially the magnetic field is perpendicular to the plane of the ring. The ring is rotated by 180° about the axis in time T.
What is the average induced emf in the ring?
A. 0
B.
C.
D. -
18N.1.HL.TZ0.33:
A ring of area S is in a uniform magnetic field X. Initially the magnetic field is perpendicular to the plane of the ring. The ring is rotated by 180° about the axis in time T.
What is the average induced emf in the ring?
A. 0
B.
C.
D. - 19M.1.HL.TZ2.29: A circular coil of wire moves through a region of uniform magnetic field directed out of the...
- 19M.2.HL.TZ2.10a: While the magnet is moving towards the ring, state why the magnetic flux in the ring is increasing.
- 19M.1.HL.TZ2.29: A circular coil of wire moves through a region of uniform magnetic field directed out of the...
- 19M.2.HL.TZ2.a: While the magnet is moving towards the ring, state why the magnetic flux in the ring is increasing.
- 19M.2.HL.TZ2.10b: While the magnet is moving towards the ring, sketch, using an arrow on Diagram 2, the direction...
-
19M.1.HL.TZ1.35:
The graph below shows the variation with time of the magnetic flux through a coil.
Which of the following gives three times for which the magnitude of the induced emf is a maximum?
A. 0, ,
B. 0, , T
C. 0, , T
D. , ,
- 19M.2.HL.TZ2.10b: While the magnet is moving towards the ring, sketch, using an arrow on Diagram 2, the direction...
- 19M.2.HL.TZ2.b: While the magnet is moving towards the ring, sketch, using an arrow on Diagram 2, the direction...
- 19M.2.HL.TZ2.10c: While the magnet is moving towards the ring, deduce the direction of the magnetic force on the...
- 19M.2.HL.TZ2.10c: While the magnet is moving towards the ring, deduce the direction of the magnetic force on the...
- 19M.2.HL.TZ2.c: While the magnet is moving towards the ring, deduce the direction of the magnetic force on the...
-
20N.2.HL.TZ0.9a:
Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.
-
20N.1.HL.TZ0.35:
A rectangular coil rotates at a constant angular velocity. At the instant shown, the plane of the coil is at right angles to the line . A uniform magnetic field acts in the direction .
What rotation of the coil about a specified axis will produce the graph of electromotive force (emf) against time ?
A. Through about
B. Through about
C. Through about
D. Through about
-
20N.1.HL.TZ0.35:
A rectangular coil rotates at a constant angular velocity. At the instant shown, the plane of the coil is at right angles to the line . A uniform magnetic field acts in the direction .
What rotation of the coil about a specified axis will produce the graph of electromotive force (emf) against time ?
A. Through about
B. Through about
C. Through about
D. Through about
- 19N.1.HL.TZ0.33: X and Y are two plane coils parallel to each other that have a common axis. There is a constant...
- 19N.1.HL.TZ0.33: X and Y are two plane coils parallel to each other that have a common axis. There is a constant...
- 19N.1.HL.TZ0.34: A coil is rotated in a uniform magnetic field. An alternating emf is induced in the coil. What is...
- 19N.1.HL.TZ0.34: A coil is rotated in a uniform magnetic field. An alternating emf is induced in the coil. What is...
-
20N.2.HL.TZ0.9a:
Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.
-
20N.2.HL.TZ0.a:
Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.
-
21M.1.HL.TZ2.35:
A magnet connected to a spring oscillates above a solenoid with a 240 turn coil as shown.
The graph below shows the variation with time of the emf across the solenoid with the period, , of the system shown.
The spring is replaced with one that allows the magnet to oscillate with a higher frequency. Which graph shows the new variation with time of the current in the resistor for this new set-up?
-
21M.1.HL.TZ2.35:
A magnet connected to a spring oscillates above a solenoid with a 240 turn coil as shown.
The graph below shows the variation with time of the emf across the solenoid with the period, , of the system shown.
The spring is replaced with one that allows the magnet to oscillate with a higher frequency. Which graph shows the new variation with time of the current in the resistor for this new set-up?
- 21M.1.HL.TZ1.33: A conducting ring encloses an area of 2.0 cm2 and is perpendicular to a magnetic field...
- 21M.2.HL.TZ2.7b: A pendulum with a metal bob comes to rest after 200 swings. The same pendulum, released from the...
-
21N.2.HL.TZ0.5a:
Show that the speed of the loop is 20 cm s−1.
- 21M.2.HL.TZ2.7b: A pendulum with a metal bob comes to rest after 200 swings. The same pendulum, released from the...
- 21M.2.HL.TZ2.b: A pendulum with a metal bob comes to rest after 200 swings. The same pendulum, released from the...
- 21M.1.HL.TZ1.33: A conducting ring encloses an area of 2.0 cm2 and is perpendicular to a magnetic field...
- 21M.1.HL.TZ1.34: The conservation of which quantity explains Lenz’s law? A. Charge B. Energy C. Magnetic...
- 21M.1.HL.TZ1.34: The conservation of which quantity explains Lenz’s law? A. Charge B. Energy C. Magnetic...
-
21N.2.HL.TZ0.5a:
Show that the speed of the loop is 20 cm s−1.
- 21N.1.HL.TZ0.33: A small magnet is released from rest to drop through a stationary horizontal conducting...
- 21N.1.HL.TZ0.33: A small magnet is released from rest to drop through a stationary horizontal conducting...
-
21N.2.HL.TZ0.a:
Show that the speed of the loop is 20 cm s−1.
-
21N.2.HL.TZ0.5b.i:
Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage in the loop.
-
21N.2.HL.TZ0.5b.i:
Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage in the loop.
-
21N.2.HL.TZ0.b.i:
Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage in the loop.
-
21N.2.HL.TZ0.5b.ii:
Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.
- 22M.1.HL.TZ2.35: A conducting bar with vertices PQRS is moving vertically downwards with constant velocity v...
-
21N.2.HL.TZ0.5b.ii:
Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.
- 22M.1.HL.TZ2.35: A conducting bar with vertices PQRS is moving vertically downwards with constant velocity v...
- 22M.2.HL.TZ2.8a.i: Write down the maximum magnitude of the rate of change of flux linked with the coil.
-
21N.2.HL.TZ0.b.ii:
Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.
-
21N.2.HL.TZ0.5c.i:
There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.
-
21N.2.HL.TZ0.5c.i:
There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.
- 22M.2.HL.TZ2.8a.i: Write down the maximum magnitude of the rate of change of flux linked with the coil.
- 22M.2.HL.TZ2.a.i: Write down the maximum magnitude of the rate of change of flux linked with the coil.
- 22M.2.HL.TZ2.8c: Predict the changes to the graph when the magnet is dropped from a lower height above the coil.
-
21N.2.HL.TZ0.c.i:
There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.
-
22M.1.HL.TZ1.34:
The graph shows the variation of magnetic flux in a coil with time .
What represents the variation with time of the induced emf across the coil?
- 22M.2.HL.TZ2.8c: Predict the changes to the graph when the magnet is dropped from a lower height above the coil.
- 22M.2.HL.TZ2.c: Predict the changes to the graph when the magnet is dropped from a lower height above the coil.
-
22M.2.HL.TZ2.8a.ii:
State the fundamental SI unit for your answer to (a)(i).
-
22M.2.HL.TZ2.8a.ii:
State the fundamental SI unit for your answer to (a)(i).
-
22M.2.HL.TZ2.a.ii:
State the fundamental SI unit for your answer to (a)(i).
-
22M.1.HL.TZ1.34:
The graph shows the variation of magnetic flux in a coil with time .
What represents the variation with time of the induced emf across the coil?
- 22M.2.HL.TZ2.8b.i: Explain why the graph becomes negative.
- 22M.2.HL.TZ2.8b.i: Explain why the graph becomes negative.
- 22M.2.HL.TZ2.b.i: Explain why the graph becomes negative.
- 22M.2.HL.TZ1.8c.i: The switch is closed at time t = 0. Explain how the voltmeter reading varies after the switch is...
-
23M.2.HL.TZ1.7a:
Explain, by reference to Faraday’s law of electromagnetic induction, why there is an electromotive force (emf) induced in the loop as it leaves the region of magnetic field.
- 22M.2.HL.TZ1.8c.i: The switch is closed at time t = 0. Explain how the voltmeter reading varies after the switch is...
- 22M.2.HL.TZ1.c.i: The switch is closed at time t = 0. Explain how the voltmeter reading varies after the switch is...
-
22M.2.HL.TZ1.8c.ii:
Determine the average emf induced across coil Y in the first 3.0 ms.
-
22M.2.HL.TZ1.8c.ii:
Determine the average emf induced across coil Y in the first 3.0 ms.
-
22M.2.HL.TZ1.c.ii:
Determine the average emf induced across coil Y in the first 3.0 ms.
- 22N.1.HL.TZ0.33: A resistor connects two parallel conducting rails a distance d apart. A conducting bar rolls...
- 22N.1.HL.TZ0.33: A resistor connects two parallel conducting rails a distance d apart. A conducting bar rolls...
- 22N.1.HL.TZ0.34: Two coils of wire are wound around an iron cylinder. One coil is connected in a circuit with...
- 22N.1.HL.TZ0.34: Two coils of wire are wound around an iron cylinder. One coil is connected in a circuit with...
- 22M.2.HL.TZ2.8b.ii: Part of the graph is above the t-axis and part is below. Outline why the areas between the t-axis...
- 22M.2.HL.TZ2.8b.ii: Part of the graph is above the t-axis and part is below. Outline why the areas between the t-axis...
- 22M.2.HL.TZ2.b.ii: Part of the graph is above the t-axis and part is below. Outline why the areas between the t-axis...
-
23M.2.HL.TZ1.7a:
Explain, by reference to Faraday’s law of electromagnetic induction, why there is an electromotive force (emf) induced in the loop as it leaves the region of magnetic field.
-
23M.1.HL.TZ1.34:
Wire XY moves perpendicular to a magnetic field in the direction shown.
The graph shows the variation with time of the displacement of XY.
What is the graph of the electromotive force (emf) ε induced across XY?
-
23M.1.HL.TZ1.34:
Wire XY moves perpendicular to a magnetic field in the direction shown.
The graph shows the variation with time of the displacement of XY.
What is the graph of the electromotive force (emf) ε induced across XY?
-
23M.2.HL.TZ1.a:
Explain, by reference to Faraday’s law of electromagnetic induction, why there is an electromotive force (emf) induced in the loop as it leaves the region of magnetic field.
- 23M.1.HL.TZ2.32: A single loop of wire of resistance 10 Ω has its plane perpendicular to a changing magnetic...
- 23M.1.HL.TZ2.32: A single loop of wire of resistance 10 Ω has its plane perpendicular to a changing magnetic...