Fleming’s Left-Hand Rule is a handy way to figure out the direction of force in an electromagnetic system. To use this rule, you’ll need to use your left hand in a specific way. It’s important to remember that this rule uses conventional current, which flows from positive to negative, and doesn’t consider electron flow.
Fleming’s Left-Hand Rule helps us determine how a coil will move when the electromagnetic field interacts with a magnetic field. By knowing which end of the wire is connected to the positive or negative terminal, we can predict the direction of the force acting on the wire.
Here’s how you can use your left hand to apply Fleming’s Left-Hand Rule:
In this setup:
Let’s look at a couple of examples to understand this better:
If the conventional current is coming towards you and the magnetic field is going from left to right, point your second finger towards you and your first finger in the direction of the magnetic field. Your thumb will point upwards, showing that the force on the wire will move it upwards.
If the conventional current is reversed and moving away from you, flip your hand so that your second finger points away from you. Keep your first finger pointing in the direction of the magnetic field. Your thumb will now point downward, indicating that the force on the wire will move it downwards.
When the wire is wrapped into a coil, consider the coil as having two halves. On the left half, if the conventional current flows away from you, it results in a downward force. On the right side, if the conventional current flows towards you, it results in an upward force. These combined forces cause the coil to rotate.
That’s all for this lesson! Keep exploring and learning more about electromagnetism. You can find more resources and examples online to help reinforce these concepts.
Practice using Fleming’s Left-Hand Rule by positioning your hand according to different scenarios. Imagine various directions for the current and magnetic field, and use your hand to determine the force direction. Share your findings with a classmate to see if you both agree on the direction of the force.
Create a simple electromagnet using a battery, wire, and nail. Use your left hand to predict the direction of the force when the current flows through the wire. Test your prediction by observing the movement of the nail when placed near a magnetic field.
Use a compass to map the magnetic field around a bar magnet. Then, apply Fleming’s Left-Hand Rule to predict the force direction on a current-carrying wire placed in this field. Draw a diagram to illustrate your predictions and compare with actual observations.
In groups, role-play as electrons, magnetic fields, and forces. Use props to represent current direction and magnetic fields. Act out scenarios where you apply Fleming’s Left-Hand Rule to determine the movement of the “force” character. Discuss how changing roles affects the outcome.
Explore online simulations that demonstrate electromagnetic interactions. Use these tools to visualize how changing the direction of current or magnetic fields affects the force on a wire. Record your observations and explain how Fleming’s Left-Hand Rule applies in each scenario.
Here’s a sanitized version of the provided YouTube transcript:
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Something we must understand is Fleming’s Left-Hand Rule. For this, we need to use our left hand in a specific way. It’s important to remember that Fleming’s rule uses conventional current and does not consider electron flow. Conventional current flows from positive to negative.
We use Fleming’s Left-Hand Rule to determine the direction in which the coil will push and pull as the electromagnetic field interacts with the magnetic field of a permanent magnet. If we visualize which end of the wire is connected to the positive or negative terminal, we can figure out the direction of the force.
To do this, extend your left hand flat with your palm facing you. Think of your thumb as representing one direction, and your fingers as representing others. Close your fingers three and four, point finger two to the right (perpendicular to your palm), and point finger one straight ahead. Your thumb should point upwards.
Your second finger indicates the direction of conventional current (from positive to negative), your first finger points in the direction of the permanent magnetic field (from north to south), and your thumb will then indicate the direction of the force.
I’ve created a PDF guide that includes some worked examples to help you remember this concept. You can find links in the video description below to get your copy.
In one example, if the conventional current is coming towards us and the magnetic field is going from left to right, we point our second finger towards us and our first finger in the direction of the magnetic field. Our thumb will then point upwards, indicating that the force on the wire will move it upwards.
In another example, if the conventional current is reversed in the wire and moving away from us, we flip our hand so that our second finger points away from us. Our first finger still points in the direction of the magnetic field, and our thumb points downward, meaning the force on the wire will move it downwards.
If we wrap the wire into a coil, we need to consider the coil as having two halves. On the left half, the conventional current is flowing away from us, resulting in a downward force. On the right side, the conventional current is flowing towards us, resulting in an upward force. Therefore, we have a combined upward and downward force, causing the coil to rotate.
That’s it for this video! To continue your learning, check out one of the videos on screen now, and I’ll catch you in the next lesson. Don’t forget to follow us on Facebook, Twitter, Instagram, LinkedIn, and visit engineeringmindset.com.
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This version maintains the essential information while removing any informal language and ensuring clarity.
Fleming – A reference to Fleming’s left-hand rule, which is used to determine the direction of force in a magnetic field. – In physics class, we used Fleming’s left-hand rule to find the direction of the force on a current-carrying wire.
Left-hand – Referring to the left-hand rule, a method to determine the direction of force, magnetic field, and current. – The teacher demonstrated the left-hand rule to show how the direction of the force is perpendicular to both the magnetic field and the current.
Rule – A guideline or principle that helps predict the behavior of physical systems, such as the direction of force in electromagnetism. – By applying the rule, we could easily determine the direction of the force acting on the wire in the magnetic field.
Current – The flow of electric charge through a conductor, typically measured in amperes. – When the current flows through the wire, it creates a magnetic field around it.
Magnetic – Relating to magnets or magnetism, often involving the force exerted by magnets. – The magnetic field around a current-carrying wire can be visualized using iron filings.
Field – A region in which a force is exerted on a charged particle, such as a magnetic or electric field. – The magnetic field around the magnet was strong enough to move the compass needle.
Force – A push or pull on an object resulting from the object’s interaction with another object, often measured in newtons. – The force exerted on the wire was calculated using the left-hand rule and the known values of current and magnetic field.
Coil – A series of loops that has been wound or gathered, often used to create magnetic fields in electromagnets. – When the coil was connected to a battery, it acted like a magnet and attracted small metal objects.
Direction – The line or path along which something moves, points, or faces, such as the direction of a magnetic field or current. – The direction of the current in the wire determines the direction of the magnetic field it produces.
Electromagnetism – The branch of physics that deals with the interaction of electric currents or fields and magnetic fields. – Electromagnetism explains how electric currents can create magnetic fields and how changing magnetic fields can induce electric currents.
