3.7.5 (magnetic fields)

Question 1

7.1.5.1
What is a magnetic field?

Answer 1

It is a force field surrounding a magnet or a current carrying wire that acts on any other magnet or current carrying wire inside the field.

Question 2

7.1.5.1
What is magnetic flux density? And what is it measured in?

Answer 2

The strength of the magnetic field. It is measured in Tesla.
It also correlates to how many field lines are in a given area

Question 3

7.1.5.1
What is the definition of a Tesla?

Answer 3

A Tesla is 1 Newton / length in meters / current in wire.

Question 4

7.1.5.1
What do 2 current carrying wires exert a force on one another?

Answer 4

When a current carrying force enters a field there is force that tries to push it out of the field which is most strong when the wire is perpendicular to the direction of the field and 0 when parallel

Question 5

7.1.5.1
How do you use Fleming’s LHR?

Answer 5

1st finger = Direction of movement
2nd finger = Direction of field
3rd finger = direction of current

Question 6

7.1.5.1
How do you use the right hand grip rule?

Answer 6

1st finger = direction of current
curl other fingers and the direction is the direction of the magnetic field lines

Question 7

7.5.1.2
What direction is the force on a moving charge in a magnetic field?

Answer 7

Perpendicular to field and direction of motion
(Flemming LHR)

Question 8

7.5.1.2
Why does a charged particle move in a circle in a magnetic field?

Answer 8

The magnetic force acts as the centripetal force which is shown by the equation r=mv/BQ

Question 9

7.5.1.2
What is the equation for the time period of a charge in a magnetic field, and its derivation?

Answer 9

2πm/BQ = T

Question 10

7.5.1.2
Describe the operation of a cyclotron

Answer 10

The charged particle gets shot into the cyclotron near the centre where it if forced into a circular path by the magnetic field causing the to exit the dee the where put into to cross to the other dee then the alternating voltage causes the acceleration to act in the opposite direction where they are once again forced into a circular motion and everytime it crosses its speed increases and this continues until it leaves

Question 11

7.5.1.2
What equation gives the cyclotron frequency?

Answer 11

BQ/2πm = f

Question 12

7.5.1.2
What equation gives the final velocity of a particle coming out of a cyclotron?

Answer 12

BQR/m = v