Physics: Principles and Problems
Physics: Principles and Problems
9th Edition
Elliott, Haase, Harper, Herzog, Margaret Zorn, Nelson, Schuler, Zitzewitz
ISBN: 9780078458132
Table of contents
Textbook solutions

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Page 789: Section Review

Exercise 27
Step 1
1 of 3
In this problem, we are given a transistor circuit in which the current gain from base to collector is 95. We are asked to find the ration between the emitter current and the base current.
Step 2
2 of 3
In order to do this, we are going to start from the equation of the transistor
$I_E=I_B+I_C$
and since we know that $I_C/I_B=95$ so we can write

$$
frac{I_E}{I_B}=1+frac{I_C}{I_B}=1+95=boxed{96}
$$

Result
3 of 3
$$
frac{I_E}{I_B}=96
$$
Exercise 28
Step 1
1 of 4
In this problem, we are given a forward-biased diode with a constant voltage drop of about 0.7 V for which the battery voltage is increased by 1 V. We are asked to find the increase of the voltage across the diode and across the resistor increase and by how much does the current increase through the resistor.
Step 2
2 of 4
a) Since the voltage across the diode is constantly 0.7 V the entirety of the voltage increase will occur across the resistor, i.e. $boxed{textrm{1 V}}$.
Step 3
3 of 4
b) Now, we can find that the current increase is given from the Ohm’s law as follows

$$
Delta I=frac{Delta V}{R}=boxed{frac{1textrm{ V}}{R}}
$$

Result
4 of 4
a) The voltage across the diode is unchanged and across the resistor increases by 1 V

b) The increase in the current is $Delta I =frac{1 textrm{ V}}{R}$.

Exercise 29
Step 1
1 of 1
The $pn$-junction diodes by definition conduct currents much better when forward-biased i.e. they have much lower resistance in comparison when they are reverse-biased.
Exercise 30
Step 1
1 of 1
In order for LED to emit the light the p-end has to be connected to the positive terminal because it has to be forward-biased.
Exercise 31
Step 1
1 of 3
In this problem we are given the base and the collector currents in a transistor and we are asked to find the current gain in this transistor.
Step 2
2 of 3
We can do so by using the definition of the current gain which is given as

$$
G=frac{I_C}{I_B}=frac{6.6times 10^{-3}}{0.055times 10^{-3}}=boxed{120}
$$

Result
3 of 3
$$
G=120
$$
Exercise 32
Step 1
1 of 1
Although in principle, one can think of this as possible, in reality, due to the different characteristics of the electronic elements this is impossible. The reason for this is the fact that in diode the $p$-end is approximately of the same thickness as the $n$-end. So if we would merge two diodes together, the $p$-layer would be twice as thick as the respective $n$-ends. However, in an $npn$ transistor, $p$-end is thin enough to allow for the passage of electrons so the former construction would not resemble a transistor whatsoever.
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Chapter 1: A Physics Toolkit
Section 1.1: Mathematics and Physics
Section 1.2: Measurement
Section 1.3: Graphing Data
Page 24: Assessment
Page 29: Standardized Test Practice
Chapter 3: Accelerated Motion
Section 3.1: Acceleration
Section 3.2: Motion with Constant Acceleration
Section 3.3: Free Fall
Page 80: Assessment
Page 85: Standardized Test Practice
Chapter 4: Forces in One Dimension
Section 4.1: Force and Motion
Section 4.2: Using Newton’s Laws
Section 4.3: Interaction Forces
Page 112: Assessment
Page 117: Standardized Test Practice
Chapter 5: Forces in Two Dimensions
Section 5.1: Vectors
Section 5.2: Friction
Section 5.3: Force and Motion in Two Dimensions
Page 140: Assessment
Page 145: Standardized Test Practice
Chapter 6: Motion in Two Dimensions
Section 6.1: Projectile Motion
Section 6.2: Circular Motion
Section 6.3: Relative Velocity
Page 164: Assessment
Page 169: Standardized Test Practice
Chapter 7: Gravitation
Section 7.1: Planetary Motion and Gravitation
Section 7.2: Using the Law of Universal Gravitation
Page 190: Assessment
Page 195: Standardized Test Practice
Chapter 8: Rotational Motion
Section 8.1: Describing Rotational Motion
Section 8.2: Rotational Dynamics
Section 8.3: Equilibrium
Page 222: Assessment
Page 227: Standardized Test Practice
Chapter 9: Momentum and Its Conservation
Chapter 10: Energy, Work, and Simple Machines
Section 10.1: Energy and Work
Section 10.2: Machines
Page 278: Assessment
Page 283: Standardized Test Practice
Chapter 11: Energy and Its Conservation
Section 11.1: The Many Forms of Energy
Section 11.2: Conservation of Energy
Page 306: Assessment
Page 311: Standardized Test Practice
Chapter 13: State of Matter
Section 13.1: Properties of Fluids
Section 13.2: Forces Within Liquids
Section 13.3: Fluids at Rest and in Motion
Section 13.4: Solids
Page 368: Assessment
Page 373: Standardized Test Practice
Chapter 14: Vibrations and Waves
Section 14.1: Periodic Motion
Section 14.2: Wave Properties
Section 14.3: Wave Behavior
Page 396: Assessment
Page 401: Section Review
Chapter 15: Sound
Section 15.1: Properties of Detection of Sound
Section 15.2: The Physics of Music
Page 424: Assessment
Page 429: Standardized Test Practice
Chapter 17: Reflections and Mirrors
Section 17.1: Reflection from Plane Mirrors
Section 17.2: Curved Mirrors
Page 478: Assessment
Page 483: Standardized Test Practice
Chapter 18: Refraction and lenses
Section 18.1: Refraction of Light
Section 18.2: Convex and Concave Lenses
Section 18.3: Applications of Lenses
Page 508: Assessment
Page 513: Standardized Test Practice
Chapter 21: Electric Fields
Section 21.1: Creating and Measuring Electric Fields
Section 21.2: Applications of Electric Fields
Page 584: Assessment
Page 589: Standardized Test Practice
Chapter 22: Current Electricity
Section 22.1: Current and Circuits
Section 22.2: Using Electric Energy
Page 610: Assessment
Page 615: Standardized Test Practice
Chapter 23: Series and Parallel Circuits
Section 23.1: Simple Circuits
Section 23.2: Applications of Circuits
Page 636: Assessment
Page 641: Standardized Test Practice
Chapter 24: Magnetic Fields
Section 24.1: Magnets: Permanent and Temporary
Section 24.2: Forces Caused by Magnetic Fields
Page 664: Assessment
Page 669: Standardized Test Practice
Chapter 25: Electromagnetic Induction
Section 25.1: Electric Current from Changing Magnetic Fields
Section 25.2: Changing Magnetic Fields Induce EMF
Page 690: Assessment
Page 695: Standardized Test Practice
Chapter 30: Nuclear Physics
Section 30.1: The Nucleus
Section 30.2: Nuclear Decay and Reactions
Section 30.3: The Building Blocks of Matter
Page 828: Assessment
Page 831: Standardized Test Practice