D.4 Induction

Outline how an emf is generated in the coil.

Outline how an emf is generated in the coil.

Outline how an emf is generated in the coil.

Explain why the magnitude of the emf is related to the amplitude of the ground movement.

Explain why the magnitude of the emf is related to the amplitude of the ground movement.

Explain why the magnitude of the emf is related to the amplitude of the ground movement.

In one particular event, a maximum emf of 65 mV is generated in the geophone. The geophone coil has 150 turns.

Calculate the rate of flux change that leads to this emf.

In one particular event, a maximum emf of 65 mV is generated in the geophone. The geophone coil has 150 turns.

Calculate the rate of flux change that leads to this emf.

In one particular event, a maximum emf of 65 mV is generated in the geophone. The geophone coil has 150 turns.

Calculate the rate of flux change that leads to this emf.

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.

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.

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.

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, $\frac{T}{4}$, $\frac{T}{2}$

B. 0, $\frac{T}{2}$, T

C. 0, $\frac{T}{4}$, T

D. $\frac{T}{4}$, $\frac{T}{2}$, $\frac{3T}{4}$

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, $\frac{T}{4}$, $\frac{T}{2}$

B. 0, $\frac{T}{2}$, T

C. 0, $\frac{T}{4}$, T

D. $\frac{T}{4}$, $\frac{T}{2}$, $\frac{3T}{4}$

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 $ZZ\mathit{\text{'}}$. A uniform magnetic field acts in the direction $ZZ\mathit{\text{'}}$.

What rotation of the coil about a specified axis will produce the graph of electromotive force (emf) $E$ against time $t$?

A.  Through $\frac{\mathrm{\pi }}{2}$ about $ZZ\mathit{\text{'}}$

B.  Through $\mathrm{\pi }$ about $YY\mathit{\text{'}}$

C.  Through $\frac{\mathrm{\pi }}{2}$ about $XX\mathit{\text{'}}$

D.  Through $\mathrm{\pi }$ about $XX\mathit{\text{'}}$

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 $ZZ\mathit{\text{'}}$. A uniform magnetic field acts in the direction $ZZ\mathit{\text{'}}$.

What rotation of the coil about a specified axis will produce the graph of electromotive force (emf) $E$ against time $t$?

A.  Through $\frac{\mathrm{\pi }}{2}$ about $ZZ\mathit{\text{'}}$

B.  Through $\mathrm{\pi }$ about $YY\mathit{\text{'}}$

C.  Through $\frac{\mathrm{\pi }}{2}$ about $XX\mathit{\text{'}}$

D.  Through $\mathrm{\pi }$ about $XX\mathit{\text{'}}$

Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.

Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.

Explain, by reference to Faraday’s law of induction, how an electromotive force (emf) is induced in the coil.

The frequency of the generator is doubled with no other changes being made. Draw, on the axes, the variation with time of the voltage output of the generator.

The frequency of the generator is doubled with no other changes being made. Draw, on the axes, the variation with time of the voltage output of the generator.

The frequency of the generator is doubled with no other changes being made. Draw, on the axes, the variation with time of the voltage output of the generator.

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 $t$ of the emf across the solenoid with the period, $T$, 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 $t$ of the current $I$ in the resistor for this new set-up?

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 $t$ of the emf across the solenoid with the period, $T$, 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 $t$ of the current $I$ in the resistor for this new set-up?

Show that the speed of the loop is 20 cm s⁻¹.

Show that the speed of the loop is 20 cm s⁻¹.

Show that the speed of the loop is 20 cm s⁻¹.

Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage $\Phi$ in the loop.

Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage $\Phi$ in the loop.

Sketch, on the axes, a graph to show the variation with time of the magnetic flux linkage $\Phi$ in the loop.

Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.

Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.

Sketch, on the axes, a graph to show the variation with time of the magnitude of the emf induced in the loop.

There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.

There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.

There are 85 turns of wire in the loop. Calculate the maximum induced emf in the loop.

The graph shows the variation of magnetic flux $\Phi$ in a coil with time $t$.

What represents the variation with time of the induced emf $\epsilon$ across the coil?

The graph shows the variation of magnetic flux $\Phi$ in a coil with time $t$.

What represents the variation with time of the induced emf $\epsilon$ across the coil?

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?

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?

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?

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?

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.

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.

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.