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### Question limit

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### 78 True/False questions

1. numberA generator produces changing____, because of its constant rotating

2. energyUse the ___ right hand rule to figure out the direction of current flow in the wire

3. Electromagnetic RadiationMaxwell predicted that light was ___-

4. perpendicularOnly the portion of the magnetic field____ to the wire will induce current in it

5. Lenz's lawYou can use ____ to find resistance

6. James Clerk Maxwell____created a set of equations that explain the relationship between electric and magnetic fields

7. charged particularInduced current is greatest if the wire and magnetic field are_____ to each other

8. -speed of wire or magnetic field motion
-length of wire in the field
-strength of magnetic field
three ways to induce current

9. wave-particle duality of lightElectromagnetic force obeys the ____ - as the two objects move further apart the force between them weakens

10. magnetic fieldIf the applied field changes, the _____ helps to keep it constant

11. 12VCar batteries provide a constant DC emf of ___

12. back emfwhen the armature is perpendicular to the magnetic field in a generator, you get____

13. induced fieldElectric and magnetic forces are aspects of a ____ - called electromagnetic force

14. AC can be converted to DCadd rings (slip rings) and brushes to the end of the loops, the moving rings counter the changing current and create direct current for a circuit

15. 230 000VUse the ___ right hand rule to figure out the direction of current flow in the wire

16. equation for multiple loopsN∆ϕM/∆t

17. transformer equation∆V2/∆V1 = N2/N1

18. Mis the mutual inductance of the two-coil system

19. reduceUse the ___ right hand rule to figure out the direction of current flow in the wire

20. particlesLow-energy photons behave more like ___

21. electromagnetic in natureMaxwell predicted that light was ___-

22. M__ depends on the shape of the coils and how they are orientated to each other

23. Step-up transformer_____ are only 90-99% efficient - power is lost due to small currents induced by changing magnetic field and resistance in the wires

24. Real transformers_____ are only 90-99% efficient - power is lost due to small currents induced by changing magnetic field and resistance in the wires

25. electronsThe magnetic field force pushes the___ through the wire

26. emf from one loopWhen you have multiple loops, you multiple the number of loops (N) by the ____

27. orientationThe magnetic field force pushes the___ through the wire

28. emfA generator produces changing____, because of its constant rotating

29. emf for generator (maximum)emf = NAβω

30. decreaseThe magnetic field force pushes the___ through the wire

31. -rotate a wire
-drag a wire through magnetic field
-move a magnetic field across a wire
three ways to induce current

32. increaseAn decrease in emf means an____ in current

33. Michael FaradayElectric and magnetic forces are aspects of a ____ - called electromagnetic force

34. transverse waveselectromagnetic waves are ___

35. The Ignition coilThe current induced in the wire by moving through a magnetic field will generate its own _______

36. lens law"The magnetic field of an induced current is in a direction to produce a field that oppose the change causing it"

37. bar magnetThe induced magnetic field is similar to a _____- and creates a force that repels the original magnetic field

38. single forceElectric and magnetic forces are aspects of a ____ - called electromagnetic force

39. rightOscillating Electric and Magnetic waves - at___ angles to each other

40. accelerating chargesAll EM waves are produced by ____ - a charge moves up/down through the wave at a certain frequency

41. Ohm's LawYou can use ____ to find resistance

42. parallelif the angle is zero the wire is____ to the magnetic field

43. volt (V)emf unit is the

44. photonA particle of light is called a____ - carries energy, but has no mass

45. permanent magnetCurrent is supplied to loops and that magnetic field repels ______ and causes the loops to rotate

46. transformersA device that increases or decreases the emf of alternating current

47. Step-down transformerdecreases the emf, N2is less than N1

48. emf & currentEffective ___ and effective ____ are the average values in the AC circuit - called Irms

49. wavesAs the coil moves out of the magnetic field the induced field is in the_____ direction as the original and they attract each other

50. wire&wireBecause AC current changes direction, the____ and____ in an AC circuit is not constant

51. emf & currentAs the loop rotates from one arm being up to the other being up, the current flow will change direction - producing ____

52. inverse square lawElectromagnetic force obeys the ____ - as the two objects move further apart the force between them weakens

53. Mutual inductanceAs the loop rotates from one arm being up to the other being up, the current flow will change direction - producing ____

54. Mutual inductance____ is the ability of one circuit to induce emf in a nearby circuit in the presence of a changing magnetic field

55. sameLow-energy photons behave more like ___

56. Heinrich Hertz___performed experiments that generated and detected EM waves and confirmed Maxwell's predictions.

57. first coil called primarycurrent in this coil magnetizes the iron core

58. 0 emfwhen the armature is perpendicular to the magnetic field in a generator, you get____

59. Second coil called secondarycurrent runs through the 2nd coil because it is wrapped around magnetized iron

60. 3rdUse the ___ right hand rule to figure out the direction of current flow in the wire

61. mechanical energywho first demonstrated the principle of electromagnetic induction

62. ωis the angular speed of rotation of the loop (2πf)

63. perpendicularSome high energy EM waves will behave like____

64. motorA particle of light is called a____ - carries energy, but has no mass

65. oppositeA particle of light is called a____ - carries energy, but has no mass

66. particlesHigh-energy photons behave more like____

67. size & rotatingChanging the ___ of the loops of wire or _____ the loop in the magnetic field will change the amount of induced current

68. CHANGEThe induced field does not oppose applied field, but the____ in the applied field

69. maximum emfwhen the armature is parallel to the magnetic field in a generator, you get ____

70. emfis the mutual inductance of the two-coil system

71. potential differenceThe _____ supplied to the motor equals the applied emf minus the back emf, this also reduces current

72. Equation for single loopemf = -∆ϕM/∆t

73. AC currentOscillating Electric and Magnetic waves - at___ angles to each other

74. Back emfwhen the armature is perpendicular to the magnetic field in a generator, you get____

75. frequencyAs a motor turns more quickly, the net emf and net current in the coil___

76. electromagnetic wavesEnergy transported by EM waves is called ____

77. Electromagnetic inductionproducing current in a wire by placing it in a changing magnetic field

78. Faraday's Law of Induction∆V2/∆V1 = N2/N1