The motor effect and electric motorsIB MYP Physics: Flashcards
What these 13 flashcards ask
- What is the motor effect?
- What affects the size of the force on a wire in a field?
- What happens to the force if the current is reversed?
- When is the force on a wire in a field zero?
- Which hand is used for the motor effect?
- What do the first finger, second finger and thumb show?
- What does a d.c. motor transfer energy from and to?
- Why do the two sides of a motor coil move in opposite directions?
- What does a split-ring commutator do?
- What is the job of the brushes in a motor?
- Name three ways to make a d.c. motor turn faster.
- How do you reverse the direction a motor turns?
- How does a loudspeaker work?
Exam questions on The motor effect and electric motors
- In a demonstration in Istanbul, a copper rod rests on two horizontal metal rails between the poles of a strong horseshoe magnet. When a current from a d.c. supply is passed through the rod, the rod rolls along the rails.State two changes that would increase the force on the rod.2 marks
- A straight horizontal wire passes at right angles between the poles of a large magnet. The north pole is on the left and the south pole is on the right, so the magnetic field points to the right. The conventional current in the wire flows away from the observer.The poles of the magnet are swapped and the current is also reversed. State the direction of the force on the wire and explain your answer.2 marks
- Students in Nairobi build a model d.c. motor. A rectangular coil of wire is placed between two magnets and connected to a battery through a split-ring commutator and carbon brushes.Explain why the coil starts to turn when the battery is connected.3 marks
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).