P4.4 Motor Effect

• What is the motor effect?

  A current carrying wire in a magnetic field experiences a force
• What happens when a current carrying wire is placed between two magnets?

  The wire experiences a force due to magnetic field interaction
• At what angle does a wire experience the full force in a magnetic field?

  At exactly 90 degrees to the magnetic field
• What happens if the wire is at a slight angle to the magnetic field?

  It will feel slightly less force
• What is the result if the wire runs in the same direction as the magnetic field?

  It will feel no force at all
• What two directions do we need to know to find the direction of the force?


  The direction of the magnetic field and the current
• What rule do we use to determine the direction of the force?

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

  Thumb up, first finger forwards, second finger out
• What does the first finger represent in Fleming's left-hand rule?

  The direction of the magnetic field
• What does the second finger represent in Fleming's left-hand rule?

  The direction of the current
• What does the thumb represent in Fleming's left-hand rule?

  The direction of the force felt by the wire
• In the scenario with the horseshoe magnet, where is the magnetic field pointing?

  Downwards from north to south
• What happens when the power source is turned on in the horseshoe magnet scenario?

  The rails generate their own magnetic field
• How do the magnetic fields interact in the horseshoe magnet scenario?

  The rails' field interacts with the horseshoe's field
• What is the equation to calculate the strength of the force?

  f = b i l
• What does the variable 'f' represent in the equation?

  Force measured in newtons
• What does the variable 'b' represent in the equation?

  Magnetic flux density in teslas
• What does the variable 'i' represent in the equation?

  Current measured in amperes
• What does the variable 'L' represent in the equation?

  Length of the wire in meters
• What are the steps to calculate the force on a wire in a magnetic field?

  1. Ensure all figures are in correct units
  2. Use the equation: $f =$$b i l$
  3. Plug in values for $b$, $i$, and $l$
  4. Calculate the force
• What are the key concepts of the motor effect?

  • Interaction of magnetic fields
  • Force on current carrying wire
  • Importance of angle (90 degrees)
  • Use of Fleming's left-hand rule
  • Calculation of force using $f =$$b i l$
• What is the motor effect?

  The motor effect is when a conductor carrying a current is placed in a magnetic field, the magnet producing a field and the conductor will exert a force on each other.
• When will a wire carrying current experience a larger force: when it is parallel to the magnetic field, or perpendicular to the magnetic field?


  To experience a full force, a current-carrying wire must be placed perpendicular to the magnetic field.
• What is Fleming's left hand rule?



  A technique used to figure out the direction of the force experienced by a current carrying wire in a magnetic field.

  
• Give 4 ways to increase the strength of the motor effect.


  1. Increase the current.
  2. add more coils.
  3. Add an iron core if u have a coil.
  4. Use stronger magnets.
• What is the formula to find the force exerted by the motor effect?


  F = BIL

  F= force exerted on wire.

  B= Magnetic field strength .

  I= current in wire.

  L= Length of wire that crosses the magnetic field.
• A current carrying wire in the presence of a magnetic field will experience a force. This is called the motor effect.
• To experience the full force, a current carrying wire must be placed perpendicular to the magnetic field.
• Fleming's left hand rule can be used to tell us the direction of the force experienced by a current carrying wire in a magnetic field.

  In the diagram above, match the letters A to C with what they represent in Fleming's left hand rule:

  Direction of the current: C

  Direction of the force: A

  Direction of the magnetic field: B

  
• Use Fleming's left hand rule to find the direction of the force experienced by the wire.

  Downwards

  
• The force (F) experienced by the wire is determined by:

  1. The current (I) in the wire
  2. The magnetic field strength (B). This is also called magnetic flux density.
  3. The length (L) of the wire that crosses the magnetic field.

  The formula to calculate the force is:


  F=BIL
• The magnetic field strength (also known as magnetic flux density) is measured in:


  Teslas (T)
• When will a wire carrying a current experience a large force: when it is parallel to the magnetic field or perpendicular to the magnetic field?


  To experience the full force, a current-carrying wire must be placed perpendicular to the magnetic field.
• What is the motor effect?


  The motor effect is the phenomenon that when a conductor carrying current is placed in a magnetic field, the magnet producing the field and the conductor will exert a force on each other.