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
• What is required for a wire to experience the full force in a magnetic field?

  The wire must be 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?

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

  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 in the wire
• 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, what direction does the magnetic field point?

  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 you determine the direction of the force in the horseshoe magnet scenario?

  Use Fleming's left-hand rule
• What is the equation to calculate the strength of the force on the wire?

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

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

  Magnetic flux density in teslas
• What does the variable 'i' represent in the equation f = b i l?

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

  Length of the wire in meters
• How do you convert 10 centimeters to meters for the calculation?

  Divide by 100 to get 0.1 meters
• What is the force experienced by a wire with a 5 amp current in a 0.4 tesla magnetic field?

  0.2 newtons
• 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 (magnetic flux density), i (current), and l (length)
  4. Calculate the force
• What are the key concepts of the motor effect?

  • A current carrying wire experiences a force in a magnetic field
  • The force direction is determined by Fleming's left-hand rule
  • The strength of the force can be calculated using $f =$$b i l$