Download Slide 1

Chapter 23
Circuits
© 2010 Pearson Education, Inc.
PowerPoint® Lectures for
College Physics: A Strategic Approach, Second Edition
23 Circuits
© 2010 Pearson Education, Inc.
Slide 23-2
© 2010 Pearson Education, Inc.
Slide 23-3
© 2010 Pearson Education, Inc.
Slide 23-4
© 2010 Pearson Education, Inc.
Slide 23-5
Drawing Circuit Diagrams
© 2010 Pearson Education, Inc.
Slide 23-12
Checking Understanding
The following circuit has a battery, two capacitors and a resistor.
Which of the following circuit diagrams is the best representation of
the above circuit?
© 2010 Pearson Education, Inc.
Slide 23-13
Answer
The following circuit has a battery, two capacitors and a resistor.
Which of the following circuit diagrams is the best representation of
the above circuit?
A
© 2010 Pearson Education, Inc.
Slide 23-14
Kirchhoff’s Junction Law
© 2010 Pearson Education, Inc.
Slide 23-15
Kirchhoff’s Loop Law
© 2010 Pearson Education, Inc.
Slide 23-16
Using Kirchhoff’s Laws
© 2010 Pearson Education, Inc.
Slide 23-17
Checking Understanding
The diagram below shows a segment of a circuit. What is the
current in the 200 resistor?
A.
B.
C.
D.
E.
0.5 A
1.0 A
1.5 A
2.0 A
There is not enough information to decide.
© 2010 Pearson Education, Inc.
Slide 23-18
Answer
The diagram below shows a segment of a circuit. What is the
current in the 200 resistor?
A.
B.
C.
D.
E.
0.5 A
1.0 A
1.5 A
2.0 A
There is not enough information to decide.
© 2010 Pearson Education, Inc.
Slide 23-19
Checking Understanding
The diagram below shows a circuit with two batteries and three
resistors. What is the potential difference across the 200
resistor?
A.
B.
C.
D.
E.
2.0 V
3.0 V
4.5 V
7.5 V
There is not enough information to decide.
© 2010 Pearson Education, Inc.
Slide 23-20
Answer
The diagram below shows a circuit with two batteries and three
resistors. What is the potential difference across the 200
resistor?
A.
B.
C.
D.
E.
2.0 V
3.0 V
4.5 V
7.5 V
There is not enough information to decide.
© 2010 Pearson Education, Inc.
Slide 23-21
Series Resistors
© 2010 Pearson Education, Inc.
Slide 23-22
Parallel Resistors
© 2010 Pearson Education, Inc.
Slide 23-23
Example Problems
There is a current of 1.0 A in the circuit below. What is the
resistance of the unknown circuit element?
What is the current out of the battery?
© 2010 Pearson Education, Inc.
Slide 23-24
Example Problem
What is the current supplied by the battery in the following circuit?
© 2010 Pearson Education, Inc.
Slide 23-25
Example Problem
Find the current in and the potential difference across each of the
resistors in the following circuit.
© 2010 Pearson Education, Inc.
Slide 23-26
Example Problems
What is the equivalent resistance of the following circuit?
Find the current in and the potential difference across each
element in the following circuit.
© 2010 Pearson Education, Inc.
Slide 23-27
Example Problem
As we saw in the previous chapter, a resistor connected to a power
supply works as a heater. Suppose an investigator is using a resistor
(a length of nichrome wire in an insulating sheath) connected to a
battery to warm a solution in the laboratory. It’s a simple circuit:
A.
What power does the resistor provide to warm the solution?
The investigator then decides that this warming is happening too
slowly. She has another resistor, but doesn’t have another battery.
She needs to connect both resistors and the battery into a single
circuit.
B.
Which of the following circuits will provide more power?
© 2010 Pearson Education, Inc.
Slide 23-28
Analyzing Complex Circuits
© 2010 Pearson Education, Inc.
Slide 23-29
Capacitor Combinations
© 2010 Pearson Education, Inc.
Slide 23-30
Checking Understanding
Which of the following combinations of capacitors has the highest
capacitance?
© 2010 Pearson Education, Inc.
Slide 23-31
Answer
Which of the following combinations of capacitors has the highest
capacitance?
B
© 2010 Pearson Education, Inc.
Slide 23-32
Checking Understanding
Which of the following combinations of capacitors has the lowest
capacitance?
© 2010 Pearson Education, Inc.
Slide 23-33
Answer
Which of the following combinations of capacitors has the lowest
capacitance?
C
© 2010 Pearson Education, Inc.
Slide 23-34
RC Circuits
© 2010 Pearson Education, Inc.
Slide 23-35
Checking Understanding
The following circuits contain capacitors that are charged to 5.0
V. All of the switches are closed at the same time. After 1 second
has passed, which capacitor is charged to the highest voltage?
© 2010 Pearson Education, Inc.
Slide 23-36
Answer
The following circuits contain capacitors that are charged to 5.0
V. All of the switches are closed at the same time. After 1 second
has passed, which capacitor is charged to the highest voltage?
C
© 2010 Pearson Education, Inc.
Slide 23-37
Checking Understanding
The following circuits contain capacitors that are charged to 5.0
V. All of the switches are closed at the same time. After 1 second
has passed, which capacitor is charged to the lowest voltage?
© 2010 Pearson Education, Inc.
Slide 23-38
Answer
The following circuits contain capacitors that are charged to 5.0
V. All of the switches are closed at the same time. After 1 second
has passed, which capacitor is charged to the lowest voltage?
B
© 2010 Pearson Education, Inc.
Slide 23-39
Electricity in the Nervous System
The action potential
Depolarization
© 2010 Pearson Education, Inc.
Repolarization
Reestablishing resting potential
Slide 23-40
Saltatory Conduction
© 2010 Pearson Education, Inc.
Slide 23-41
Example Problem
There are some diseases that result in a thinning of the myelin
sheath that surrounds peripheral neurons—those that carry signals
between the spinal cord and the limbs. How will this thinning affect
nerve conduction speed? Explain this using the model for nerve
conduction developed in the chapter.
© 2010 Pearson Education, Inc.
Slide 23-42
Summary
© 2010 Pearson Education, Inc.
Slide 23-43
Summary
© 2010 Pearson Education, Inc.
Slide 23-44
Additional Questions
1. In the circuit below, the switch is initially open and bulbs A and B
are of equal brightness. When the switch is closed, what
happens to the brightness of the two bulbs?
A.
B.
C.
D.
The brightness of the bulbs is not affected.
Bulb A becomes brighter, bulb B dimmer.
Bulb B becomes brighter, bulb A dimmer.
Both bulbs become brighter.
© 2010 Pearson Education, Inc.
Slide 23-45
Answer
1. In the circuit below, the switch is initially open and bulbs A and B
are of equal brightness. When the switch is closed, what
happens to the brightness of the two bulbs?
A.
B.
C.
D.
The brightness of the bulbs is not affected.
Bulb A becomes brighter, bulb B dimmer.
Bulb B becomes brighter, bulb A dimmer.
Both bulbs become brighter.
© 2010 Pearson Education, Inc.
Slide 23-46
Additional Questions
2. In the circuit shown below, the switch is initially closed and the
bulb glows brightly. When the switch is opened, what happens
to the brightness of the bulb?
A.
B.
C.
D.
E.
The brightness of the bulb is not affected.
The bulb gets dimmer.
The bulb gets brighter.
The bulb initially brightens, then dims.
The bulb initially dims, then brightens.
© 2010 Pearson Education, Inc.
Slide 23-47
Answer
2. In the circuit shown below, the switch is initially closed and the
bulb glows brightly. When the switch is opened, what happens
to the brightness of the bulb?
A.
B.
C.
D.
E.
The brightness of the bulb is not affected.
The bulb gets dimmer.
The bulb gets brighter.
The bulb initially brightens, then dims.
The bulb initially dims, then brightens.
© 2010 Pearson Education, Inc.
Slide 23-48
Additional Example Problems
1. In the circuit shown below:
A.
B.
Rank in order, from most to least bright, the brightness
of bulbs A–D. Explain.
Describe what, if anything, happens to the brightness of
bulbs A, B, and D if bulb C is removed from its socket.
Explain.
© 2010 Pearson Education, Inc.
Slide 23-49
Additional Example Problems
2. In the circuit shown below, rank in order, from most to least
bright, the brightness of bulbs A–E. Explain.
© 2010 Pearson Education, Inc.
Slide 23-50
Additional Example Problems
3. In the circuit shown below:
A. How much power is dissipated by the 12 Ω resistor?
B. What is the value of the potential at points a, b, c, and d?
© 2010 Pearson Education, Inc.
Slide 23-51