Motor effect

• What is the motor effect?

  The motor effect is the idea that a current carrying wire in a magnetic field experiences a force.
• What happens when a current carrying wire is placed in a magnetic field?

  The wire experiences a force due to the interaction of its magnetic field with the external magnetic field.
• What is required for a wire to experience the full force in a magnetic field?

  The wire must be positioned at exactly 90 degrees to the magnetic field.
• How does the angle of the wire affect the force it experiences in a magnetic field?

  If the wire is at a slight angle, it will feel slightly less force, and if it runs in the same direction as the field, it will feel no force at all.
• What two directions do we need to know to find the direction of the force on the wire?

  We need to know the direction of the magnetic field and the direction of the current in the wire.
• What rule do we use to determine the direction of the force on the wire?

  We use Fleming's left-hand rule.
• How do you position your fingers according to Fleming's left-hand rule?

  Your thumb points up, your first finger points forwards, and your second finger points out to the side.
• What does the first finger represent in Fleming's left-hand rule?

  The first finger represents the direction of the magnetic field from north to south pole.
• What does the second finger represent in Fleming's left-hand rule?

  The second finger represents the direction of the current in the wire.
• What does the thumb represent in Fleming's left-hand rule?

  The thumb represents the direction of the force felt by the wire.
• What is a scenario where the motor effect can be observed?

  The motor effect can be observed between the two poles of a horseshoe magnet with metal rails.
• What happens when the power source is turned on in the metal rails scenario?

  The rails generate their own magnetic field, which interacts with the horseshoe magnet's field, causing a force.
• How do we determine the direction of the force in the metal rails scenario?

  We use Fleming's left-hand rule again, orienting the first finger downwards and the second finger towards us.
• What is the equation used to calculate the strength of the force on the wire?

  The equation is $F =$$BIL$.
• What do the variables in the equation $F =$$BIL$ represent?


  $F$ is force in newtons, $B$ is magnetic flux density in teslas, $I$ is current, and $L$ is the length of the wire in meters.
• How do you convert the length of the wire from centimeters to meters?

  You divide the length in centimeters by 100.
• If you have a 10 cm piece of wire, what is its length in meters?

  0.1 meters.
• What is the force experienced by a wire with a 5 amp current in a magnetic field of 0.4 teslas and a length of 0.1 meters?

  The force is 0.2 newtons.
• What are the key components needed to calculate the force on a current-carrying wire in a magnetic field?

  • Current in the wire (I)
  • Magnetic flux density (B)
  • Length of the wire (L)
  • Angle of the wire to the magnetic field (90 degrees for maximum force)
• What are the steps to apply Fleming's left-hand rule?

  1. Point your first finger in the direction of the magnetic field (north to south).
  2. Point your second finger in the direction of the current.
  3. Your thumb will then point in the direction of the force.