EM induction

Question 1

What is electromagnetic induction?

Answer 1

when magnet moved near wire, current passes through wire (detected by a sensitive meter)

emf induced in the wire

em induction occurs wheneber a wire cuts across the lines of a magnetic field

Question 2

What is induced emf? what increases it

Answer 2

emf caused by em induction in a complete circuit

increased by

moving wire faster

using stronger magnet

making wire into a coil and pushing the magnet in or out of the coil

Question 3

When is no emf induced?

Answer 3

if the wire is parallel to the magnetic field lines as it moves thrpugh the field

the wire must cut across the lines of the magnetic field for an induced emf

Question 4

What is the energy transferred from the coil to lamp equal to?

Answer 4

work done to keep the coil spinning

assuming none is lost as energy

Question 5

How does electromagnetic induction occur?

Answer 5

beam of electrons across magnetic field, each experiences force at right angles to its direction of motion and field direction

• magnetic field forces free electrons to one end away from the other end
  
  • one end becomes -ve and one +ve
  • therefore an emf is induced

when circuit is completed, this drives electrons around the circuit

Question 6

What is Fleming’s right hand rule?

Answer 6

current 3rd

field 2nd

thumb, motion of conductor