Magnet part 2

Question 1

Why is a deflected electron beam travel in circular motion?

Answer 1

force is perpendicular to the direction of motion of the electron and to the field direction

Question 2

How can direction of the force of electron worked out?

Answer 2

FLeming’s left hand rule

convention that the current direction is opposite to the direction in which the electrons move

Question 3

What happens as a charge particle moves across a central magnetic field?

Answer 3

• no work done by field
  
  • force always right angles to the velocity of the particle
  • direction changes but speed doesn’t, KE remain the same
• according to Fleming’s left hand rule, the force is always perpendicular to the velocity at any point along the path
  
  • particle moves in circular path with the force acting towards the centre of curvature of the circle path
• force causes centripetal acceleration because it is perpendicular to the velocity

Question 4

What does the radius of the orbit depend on?

Answer 4

• speed and magnetic flux density