1. Chapter
Review

2. The behavior of bar magnets

3. Our Earth itself has a magnetic field

4. Charges moving with respect to a field

5. Charges moving with respect to a field

6. Charges moving with respect to a field

7. The Right Hand Rule
Using the right hand rule, one may determine the direction of the field produced by a moving positive charge.

8. Magnetism and circular motion
F = |q|vB
If the motion is
Circular
F = mv2/R
R = mv/ |q|B
ω = v/R = |q|B/m

9. Force on a conductor with current
F = ILB

10. Applications of force on a conductor

11. Magnetic field of long straight conductor

12. B = μ0I/(2πr) Magnetic field of a long, straight wire:
r is the distance from the wire
μ0 is called the permeability of vacuum
μ0 = 4π x 10-7 T.m/A

13. Fields in two conductors side-by-side

14. Fields in two conductors side-by-side

15. F = μ0 L(I1 I2)/(2πr) F/L = μ0 (I1 I2)/(2πr)
2 wires with currents flowing in the same direction
attract each other
2 wires with currents flowing in opposite directions
repel each other
F = μ0 L(I1 I2)/(2πr)
Force per unit length
F/L = μ0 (I1 I2)/(2πr)

16. Magnetic field at the center of a circular loop B = μoI /(2R)
Currents in a loop
Magnetic field at the center of a circular loop
B = μoI /(2R)
For N loops:
B = μo NI /(2R)

17. Electromagnetic Induction

18. Does the field induce a current or not?

19. Magnetic flux at various orientations

20. Magnetic flux at various orientations

21. Magnetic flux at various orientations

22. If we have a coil with N identical turns, then
FRADAY’s LAW
When the magnetic flux ΦB changes in time, there is a an induced emf directly proportional
to the time rate of change of the magnetic flux :
ɛ = |Δ ΦB /Δt |
If we have a coil with N identical turns, then
ɛ = N |Δ ΦB /Δt |

23. Vab = vBL a b

24. Lenz’s Law

25. Lenz’s Law

26. Transformers

27. If energy completely transformed
TRANSFORMERS
V2 / V1 = N2 / N1
If energy completely transformed
V1I1 = V2I2

28. Energy associated with an induced current.
energy is stored in an electronic device.

29. The R-L circuit

30. The L-C circuit

31. In the case of an inductor with a capacitor,
the energy is transferred from the electric field
(capacitor) to magnetic field (inductor) and vice versa.
The total energy is however conserved:
The back and forth of the energy constitutes an oscillatory
behavior with a frequency ω:

32. A metal loop moves at constant velocity toward a long wire carrying a steady current , as shown in the figure . The current induced in the loop is directed
A) Clockwise B) counterclockwise C) zero

33. B out of page increasing ΔΦ out of page Bi into page
A metal loop moves at constant velocity toward a long wire carrying a steady current , as shown in the figure . The current induced in the loop is directed
A) Clockwise B) counterclockwise C) zero
B out of page increasing
ΔΦ out of page
Bi into page

34. The slide wire of the variable resistor in the figure is moved steadily to the right, increasing the resistance in the circuit. While this is being done, the current induced in the small circuit A is directed :
A) clockwise B) counterclockwise C) zero

35. I A) clockwise B) counterclockwise C) zero
I=V/R I decreases when R increases
B due to I decreases as I decreases
B out of page and decreases hence ΔΦ into page
Bi out of page I