# DC Motors

In this lesson we apply the motor effect to an electric motor to understand how it can rotate.

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!

Q1.What unit is magnetic flux density measured in?

1/8

Q2.What unit is current measured in?

2/8

Q3.What unit is length measured in?

3/8

Q4.What unit is force measured in?

4/8

Q5.Magnetic flux density is measured in which of these units?

5/8

Q6.A 0.4 m wire with 2 A flowing in it passes through a magnetic field with a magnetic flux density of 0.5 T. What force ix exerted on the wire?

6/8

Q7.A straight wire 0.10 m long carrying a current of 2.0 A is at right angles to a magnetic field. The force on the wire is 0.04 N. What is the strength of the magnetic field?

7/8

Q8.A wire that is 470 mm long hangs at right angles to a magnetic field of 1,800 μT and experiences a force of 9.5 mN. Calculate the current flowing in the wire. (2 s.f)

8/8

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!

Q1.What unit is magnetic flux density measured in?

1/8

Q2.What unit is current measured in?

2/8

Q3.What unit is length measured in?

3/8

Q4.What unit is force measured in?

4/8

Q5.Magnetic flux density is measured in which of these units?

5/8

Q6.A 0.4 m wire with 2 A flowing in it passes through a magnetic field with a magnetic flux density of 0.5 T. What force ix exerted on the wire?

6/8

Q7.A straight wire 0.10 m long carrying a current of 2.0 A is at right angles to a magnetic field. The force on the wire is 0.04 N. What is the strength of the magnetic field?

7/8

Q8.A wire that is 470 mm long hangs at right angles to a magnetic field of 1,800 μT and experiences a force of 9.5 mN. Calculate the current flowing in the wire. (2 s.f)

8/8

# 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:

# DC Motors (HT only)

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.

1/5

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

2/5

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

3/5

Q4.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.

4/5

Q5.Which way will the simple motor shown below rotate? (Hint : use Fleming's Left Hand Rule on one side of the coil)

5/5

Quiz:

# DC Motors (HT only)

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.

1/5

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

2/5

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

3/5

Q4.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.

4/5

Q5.Which way will the simple motor shown below rotate? (Hint : use Fleming's Left Hand Rule on one side of the coil)

5/5

# Lesson summary: DC Motors

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Jog

On the spot:
Dance