XC

1
XC
XL
f
fo
Z
R
f
fo
2
A copper coil is set just behind the wire loop
of this circuit. As the switch is closed,

1. a clockwise current is induced in the copper
   loop.
2. a counter clockwise current is induced in the
   copper loop.
3. no current appears in the copper loop.

3
A copper coil rests flat on a tabletop next to
the wire loop of this simple circuit. As the
switch is opened,

1. a clockwise current is induced in the copper
   loop.
2. no current appears in the copper loop.

4
A copper coil is set just behind the wire loop
of this circuit. As the switch is opened,

1. a clockwise current is induced in the copper
   loop.
2. a counter clockwise current is induced in the
   copper loop.
3. no current appears in the copper loop.

5
A
B
6 V
Compared to the voltage drop across coil A, the
voltage across coil B is 1) less than 6
V 2) 6 V 3) greater than 6 V
6
1 Amp
120 V
120 V
240 V
What is the voltage across the light
bulb? 1) 60 V 2) 120 V 3) 240 V
7
1 Amp
120 V
120 V
240 V
What is the voltage across the light
bulb? 1) 60 V 2) 120 V 3) 240 V
What is the current through the light
bulb? 1) 1/2 Amp 2) 1 Amp 3) 2 Amps
8
1 Amp
120 V
120 V
240 V
What is the voltage across the light
bulb? A) 60 V B) 120 V C) 240 V
Twice as many loops voltage doubles. THEN half
as many loops, voltage halves
What is the current through the light
bulb? A) 1/2 Amp B) 1 Amp C) 2 Amp s
Power in Power out Voltage out 120 V 240 V ?
1 Amp 120 V ? I so I 2 Amp
9

• 2) a counter clockwise current is induced in the
  copper loop.
• A clockwise current is created in the black wire
  loop, establishing a sudden magnetic
• field pointing down into the center of the
  copper coil. To counter this, the coil will
• try to create a field of its own pointing out.
  It does this with a counter clockwise current.
• 2) a counter clockwise current is induced in the
  copper loop.
• While current flows the wire loops field points
  into the screen within its center, but
• doubles back outside the loop. That means where
  the copper coil lies, the field initially
• points out. When the switch is opened, this
  field suddenly vanishes. To counter the
• disappearance of flux, the coil tried to create
  its own, which requires a clockwise
• induced current.
• a clockwise current is induced in the copper
  loop.
• The coil tried to replace the flux that starts to
  disappear as soon as the switch is opened.
• less than 6 V The voltage across B is zero only
  a changing magnetic flux induces
• an EMF. Batteries provide DC current.
• 2) 120 V Twice as many loops voltage doubles.
  THEN half as many loops, voltage halves