GCSE Standard Questions: The Motor Effect
Q1. A student investigates the electromagnetic force acting on a wire which carries an electric current. The wire is in a magnetic field. The diagram shows the circuit that the student uses.
(a) Draw an X on the diagram, with the centre of the X in the strongest part of the magnetic field.
(b) Give one change that she can make to the magnets to decrease the electromagnetic force on the wire.
(c) The student wants to change the electromagnetic force on the wire without changing the magnets or moving their position.
(i) Give one way in which she can increase the electromagnetic force.
(ii) Give one way in which she can reverse the direction of the electromagnetic force.
(Total 4 marks)
Q2. Many electrical appliances use the circular motion produced by their electric motor.
(a) Underline the appliances from the list below which have an electric motor.
- electric drill
- electric fan
- electric food mixer
- electric iron
- electric kettle
- electric screwdriver
(b) One simple design of an electric motor is shown in the diagram. It has a coil which spins between the ends of a magnet.
(i) Give two ways of reversing the direction of the forces on the coil in the electric motor.
(ii) Give two ways of increasing the forces on the coil in the electric motor.
(Total 6 marks)
Q3. When a conductor carrying an electric current is placed in a magnetic field a force may act on it.
(a) State two ways in which this force can be increased.
(b) State two ways in which this force can be made to act in the opposite direction.
(c) In what circumstance will no force act on a conductor carrying an electric current and in a magnetic field?
(Total 5 marks)