# F = B × I × l

In this lesson we learn how to apply the equation to calculate the size of the force due to the motor effect and apply it to a range of situations.

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 9

Q1.Which way do we consider 'conventional current' to flow?

1/9

Q2.Which way do the magnetic flux lines in a magnetic field point?

2/9

Q3.What angle should be between the direction of current and the direction of the magnetic field for the force that is exerted on a wire to be a maximum?

3/9

Q4.What is true about the direction of the force exerted on a wire placed in a magnetic field when a current flows in the wire.

4/9

Q5.Which of the following changes would not make the motor effect force stronger?

5/9

Q6.Which hand is used to predict the direction of the force from the motor effect?

6/9

Q7.Match up below the quantity with the finger that shows it on Fleming's Left Hand Rule.
Current (I)
Motion (F, Force)
Magnetic Field (B)

7/9

Q8.Which way will the force act here?

8/9

Q9.Which way will the force act here?

9/9

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 9

Q1.Which way do we consider 'conventional current' to flow?

1/9

Q2.Which way do the magnetic flux lines in a magnetic field point?

2/9

Q3.What angle should be between the direction of current and the direction of the magnetic field for the force that is exerted on a wire to be a maximum?

3/9

Q4.What is true about the direction of the force exerted on a wire placed in a magnetic field when a current flows in the wire.

4/9

Q5.Which of the following changes would not make the motor effect force stronger?

5/9

Q6.Which hand is used to predict the direction of the force from the motor effect?

6/9

Q7.Match up below the quantity with the finger that shows it on Fleming's Left Hand Rule.
Current (I)
Motion (F, Force)
Magnetic Field (B)

7/9

Q8.Which way will the force act here?

8/9

Q9.Which way will the force act here?

9/9

# 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:

# F = B × I × L (HT only)

This quiz will help you consolidate your learning on the motor effect equation F = B × I × l

## Question 6

Q1.Match up the quantities in the equation to the correct units shown.
Magnetic flux density
Current
Length
Force

1/5

Q2.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?

2/5

Q3.For each of the numbers below, how do we convert them ready to use in our equations.
34 mm
650 nT
265 µA
2 km
65 GA

3/5

Q4.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?

4/5

Q5.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)

5/5

Quiz:

# F = B × I × L (HT only)

This quiz will help you consolidate your learning on the motor effect equation F = B × I × l

## Question 6

Q1.Match up the quantities in the equation to the correct units shown.
Magnetic flux density
Current
Length
Force

1/5

Q2.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?

2/5

Q3.For each of the numbers below, how do we convert them ready to use in our equations.
34 mm
650 nT
265 µA
2 km
65 GA

3/5

Q4.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?

4/5

Q5.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)

5/5

# Lesson summary: F = B × I × l

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