Summary Introduction to electrodynamics

A snapshot of the summary - Introduction to electrodynamics Author: David J Griffiths ISBN: 9781108420419

• 5 Magnetostatics

• What does magnetostatics imply for the charge?

  It implies that 6the charge is in motion instead of being static

• 5.1.1 Magnetic Fields

• What happens to the wire when both current flow up?

  They are found to attract
• What happens to the wires when a current flows down and a current flows up(opposite direction)?

  The wires are found to repel.
• What does a stationary charge produce? What does a moving charge produce?

  A stationary charge only creates an E field around it whilst a moving charge also creates a B field in addition.
• How do magnetic field lines look like and how can you predict them?

  A magnetic field line circles around the wire (right-hand rule with the thumb being the current and the fingers being the b field.)
• How can such a field lead to a force? How can we predict this?

  You can use the FBI rule with your fingers our you can open up your hand with the previous wire hand rule. This way the direction of your open hand will have the direction of the force to the left.

• 5.1.2 Magnetic Forces

• How do can we call the certain magnetic force won a charge Q moving with a velocity v in a  magnetic field B?

  We call this force the Lorentz Force law. .
• What would the net force on Q become if i is also in a B field?

  When you would thus want to know the net force on Q we would have to take the presence of both electric fields and magnetic fields into consideration
• How does cyclotron motion look like?

  We know that the magnetic force has a fixed magnitude since it  is always pointing inwards. Therefore, we will have F=QvB. The magnitude of the force will be equal to  the change in the directioin which is the equal to v2/R = This comes down top P=QBR. 
• How does the cycloid motion look like?

  With the cyclotron frequency being QB/m