Download Lecture Notes: Y F Chapter 28

Electric Field:
The electric field produced by a static electric charge
acts on another static electric charge to give a force
Magnetic Field:
The magnetic filed produced by a moving electric charge
acts on another moving electric charge to give a force
r
The magnitude and position of a charge gives E
r
The magnitude and position and velocity of a charge gives B
r
The “strength” of the source of E is q
r
The “strength” of the source of B is qv
µ0
−7 N ⋅ s 2
= 4π × 10
2
C
4π
r
E =
1
q
4πε 0 r 2
r µ0 qv sin ϕ
B=
4π
r2
EXACTLY
µ0 Is deeply related to ε 0 and we will later discover that:
1
Speed of light
µ0ε 0 = 2
c
For the time being consider µ0 to be an independent constant like ε 0
Force between two infinite conductors
What if the Path around the infinite conductor is not a circle?
What if the Path does not go around the conductor?
I
Step 1: If Integral < 0, then current flows in the direction
opposite that of the thumb
I
Step 1: If Integral > 0, then current flows in the direction of thumb
Step 1: Curl the fingers of your RH in the direction of Integration
The sign of the line integral gives the direction of the current
Magnetic Field from a Solenoid
Magnetic Field from a Single Loop
Symmetry says that field lines must be concentric circles
Toroidal Solenoid
End of Chapter 28
You are responsible for the material covered in T&F Sections 28.1 -28.7
You are expected to:
•
Understand the following terms:
Law of Biot & Savart, Ampere’s Law, Solenoid,
•
Be able to calculate the magnetic field from simple geometries by integrating the law of B & S
•
Be able to calculate the magnetic field for more complex geometries using Ampere’s Law
Recommended F&Y Exercises chapter 28:
9,15,18,20,21,25,32,33