# Electromagnetic induction and generators

In this lesson we explore how a potential difference can be generated by moving a wire in a magnetic field and how this is used in ac generators to make electricity for the National Grid.

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

## Question 6

Q1.Which rule is used to work out the direction of the force exerted on a coil in a motor, when current flows within a magnetic field.

1/6

Q2.What does a force produce when it pushes on something with an axle?

2/6

Q3.Which direction will the force on the wire act?

3/6

Q4.Put the statements below into the correct order.
On one side of the coil the current flows away from us and on the...
… rotate as each force creates a moment.
… produced by the current in the magnetic field will be in opposite ...
The current flows around the coil. The magnetic field is across the coil at right angles to the axis of the coil.
… directions. Because there is a fixed axle, the coil will begin to ...
… other the current flows towards us. This means that the forces ...

4/6

Q5.What is the name of the device that, as the coil spins, makes sure that the moments on the coil always act to spin the coil in the same direction, by swapping over the electrical contact every half turn.

5/6

Q6.Which way will the simple motor shown below rotate? (Hint : use Fleming's Left Hand Rule on one side of the coil)

6/6

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

## Question 6

Q1.Which rule is used to work out the direction of the force exerted on a coil in a motor, when current flows within a magnetic field.

1/6

Q2.What does a force produce when it pushes on something with an axle?

2/6

Q3.Which direction will the force on the wire act?

3/6

Q4.Put the statements below into the correct order.
On one side of the coil the current flows away from us and on the...
… rotate as each force creates a moment.
… produced by the current in the magnetic field will be in opposite ...
The current flows around the coil. The magnetic field is across the coil at right angles to the axis of the coil.
… directions. Because there is a fixed axle, the coil will begin to ...
… other the current flows towards us. This means that the forces ...

4/6

Q5.What is the name of the device that, as the coil spins, makes sure that the moments on the coil always act to spin the coil in the same direction, by swapping over the electrical contact every half turn.

5/6

Q6.Which way will the simple motor shown below rotate? (Hint : use Fleming's Left Hand Rule on one side of the coil)

6/6

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

Quiz:

# Electromagnetic Induction (Physics only)

## Question 9

Q1.Which sentence below describes electromagnetic induction?

1/9

Q2.What is the word that describes when a potential difference is made in a coil?

2/9

Q3.Which scientist first discovered electromagnetic induction?

3/9

Q4.Which of these would not cause the direction of the potential difference to reverse when using a coil and a magnet to demonstrate the generator effect?

4/9

Q5.Which term refers to when a conductor and wire move across each other?

5/9

Q6.In which of these situations will there not be an induced potential difference?

6/9

Q7.Which direction will the magnetic field made by the induced current be?

7/9

Q8.Decide if each statement below is true or false.
A potential difference will be induced if the magnet is held stationary the coil.
An electric current will flow if the ends of the coil are connected to an external circuit.
A potential difference will not be induced if the magnet is moved up and down inside the coil.
An induced current generates a magnetic field that opposes the original change, either the movement of the conductor or the change in magnetic field.

8/9

Q9.Which of the following will increase the size of the induced potential difference

9/9

Quiz:

# Electromagnetic Induction (Physics only)

## Question 9

Q1.Which sentence below describes electromagnetic induction?

1/9

Q2.What is the word that describes when a potential difference is made in a coil?

2/9

Q3.Which scientist first discovered electromagnetic induction?

3/9

Q4.Which of these would not cause the direction of the potential difference to reverse when using a coil and a magnet to demonstrate the generator effect?

4/9

Q5.Which term refers to when a conductor and wire move across each other?

5/9

Q6.In which of these situations will there not be an induced potential difference?

6/9

Q7.Which direction will the magnetic field made by the induced current be?

7/9

Q8.Decide if each statement below is true or false.
A potential difference will be induced if the magnet is held stationary the coil.
An electric current will flow if the ends of the coil are connected to an external circuit.
A potential difference will not be induced if the magnet is moved up and down inside the coil.
An induced current generates a magnetic field that opposes the original change, either the movement of the conductor or the change in magnetic field.

8/9

Q9.Which of the following will increase the size of the induced potential difference

9/9

# Lesson summary: Electromagnetic induction and generators

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