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Questions tagged [textbook-erratum]

For questions about possible specific errors in asker's reference material. PLEASE search for the relevant errata webpage before asking. DO NOT USE THE TAG for general critique beyond the scope of the reference.

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Error concerning projectile motion in respected textbook?

In the textbook Fundamentals of Physics by R. Shankar of Yale Open Courses, appears the following assertion pertaining to a car driving off a cliff, which seems correct: This is exactly how long it ...
Trever Thompson's user avatar
4 votes
0 answers
93 views

Lorentz force error in the present 2024 version of the gravitoelectromagnetism Wikipedia page? [closed]

I noticed that the Gravitoelectromagnetism (GEM) Wikipedia page has been edited recently. The factor of 4 in the GEM Lorentz force equation is now missing. But the GEM field equations are identical to ...
rdryne's user avatar
  • 41
1 vote
1 answer
60 views

Definition of the Conformal algebra generators

In the textbook "Introduction to Conformal Field Theory" by Blumenhagen and Plauschinn (2009), Section 2.1, the generators of the Lie algebra corresponding to the conformal group for the ...
Joseph Shtok's user avatar
3 votes
1 answer
55 views

Time component of four-velocity

While reading through Spacetime and Geometry by Sean Carroll, I came across the following passage: "Don't get tricked into thinking that the timelike component of the four velocity of a particle ...
V Govind's user avatar
  • 442
2 votes
3 answers
110 views

Sign conventions for the Lagrangian from the EM Lagrangian density

In Chapter 13.6 of the 3rd edition of Goldstein's Classical Mechanics, Goldstein proposes the Lagrangian density of the electromagnetic field as: $$\mathcal{L} = -\frac{F_{\lambda \rho} F^{\lambda \...
tugboat2's user avatar
0 votes
0 answers
24 views

Is this an error in deriving the Rayleigh-Jeans law? Kunstatter and Das's Symmetry SR and QM Ultraviolet Catastrophy

My question regards G. Kunstatter and S. Das, A First Course on Symmetry, Special Relativity and Quantum Mechanics, Undergraduate Lecture Notes in Physics, https://doi.org/10.1007/978-3-030-92346-4\_8 ...
Steven Thomas Hatton's user avatar
0 votes
0 answers
91 views

Two-particle Green's function, possible typo in the book referred?

I'm trying to follow a computation in some QFT book, p64. The goal is to derive the equation of motion for the lesser Green's function $G^<$ defined as $$ G^< = \mp i {\rm Tr}\left(\rho \Psi^\...
user2820579's user avatar
1 vote
1 answer
45 views

Imhomegenous Wave Equation: Possible Born and Wolf Error

My concern involves the following lines from Principle of Optics (Born and Wolf 7th ed, 60 year anniverary, Section 1.2 pg 11). I fail to derive these equations 5,6 exactly. $$ \begin{align} \nabla^...
Fredrik Sy's user avatar
2 votes
2 answers
582 views

A ball was thrown horizontally but it has zero horizontal initial velocity? [closed]

A question I faced reads "A ball is thrown horizontally from a height of 25m and hits the ground with a speed that is 4 times its initial speed. What is the initial speed?". It said the ...
petit beauté's user avatar
1 vote
2 answers
123 views

Why does the power loss in transmission cable increase when resistance is increased?

In transmission cables, why does power loss increase when length of conductor is increased? According to the formulas V=IR and P=I²R, When we increase the length, the resistance increases, while the ...
Hufaiza Hufaiza's user avatar
7 votes
2 answers
901 views

Does the kaon participate in the weak interaction?

I'm looking at a physics textbook for A-level and in the book it states that kaons are only affected by the strong force and the electromagnetic force. Isn't this incorrect? Aren't kaons affected by ...
S Paul's user avatar
  • 109
-4 votes
1 answer
116 views

Does this question require any calculus to solve? [closed]

So, I came across this question in a book, Two spherical bodies of mass $M$ and $5M$ and radii $R$ and $2R$, respectively are released in free space with initial separation between their centers ...
Swastik 34's user avatar
2 votes
1 answer
104 views

Textbook derivation of relativistic energy

I am working through this textbook derivation, and I don't quite understand how this step is justified. I have a link to the page below but briefly the step I don't understand is the jump from $$K= \...
Zach's user avatar
  • 31
0 votes
0 answers
159 views

Important typo in Schwartz's QFT: Incorrect spinor solutions leading to wrong charge conjugation properties

Eq 11.18 in Schwartz's book reads: $$u_{\uparrow}=\sqrt{m}\begin{pmatrix}1\\0\\1\\0\end{pmatrix} u_{\downarrow}=\sqrt{m}\begin{pmatrix}0\\1\\0\\1\end{pmatrix} v_{\uparrow}=\sqrt{m}\begin{pmatrix}-1\\0\...
Bababeluma's user avatar
0 votes
1 answer
49 views

Inconsistent indices in the differential equation of infinitesimal conformal transformation

Consider the equation from CFT, \begin{equation} \partial_{\mu}\epsilon_{\nu} + \partial_{\nu}\epsilon_{\mu} = f(x)\eta_{\mu\nu}\tag{Yellow book eq. 4.3} \end{equation} which constrains the form of $\...
diracwittayah's user avatar
4 votes
1 answer
96 views

How to explain different, seemingly inconsistent, values for the mass of the alpha particle in different books?

I’m trying to calculate the energy of an $\alpha$ particle after the decay of Ra-226 following an example in a german school book and came across different values for the mass of an $\alpha$ particle. ...
Tobi's user avatar
  • 143
-1 votes
1 answer
136 views

Can Solid takes the shape of its container

My Cambridge Physics Coursebook says that Solid "takes the shape of its container". It is endorsed by Cambridge for IGCSE physics. Is it right? How is this possible. It is very Clear and ...
Home User's user avatar
0 votes
0 answers
69 views

How does rotation appear in the components of the angular momentum operator?

In Hall's Quantum Theory for Mathematicians, Chapter 17, page 369, he introduces the angular momentum operator as $\hat{J} = X \times P$ whose the third component is $$\hat{J}_3 = X_1P_2 - X_2P_1.$$ ...
CBBAM's user avatar
  • 3,350
2 votes
2 answers
102 views

The relation of time-evolution operators from Schwartz's textbook

In the section 7.2.2 of Schwartz's QFT textbook, it says: define the generation definition of time-evolution operators: $$U_{21}\equiv U(t_2,t_1)=T{\exp[-i\int^{t_2}_{t_1} dt'V_I(t')]}\tag{7.46}$$ ...
Link's user avatar
  • 33
0 votes
1 answer
28 views

Generalized forces for virtual work - Why did they drop the summation?

I am going through a PDF by Subhankar Ray & J. Shamanna on virtual work here and according to the PDF, equation 29, they write gerneralized force as: $$Q_j = -\nabla_k\tilde{V}\cdot\left(\frac{\...
Reuben's user avatar
  • 283
2 votes
1 answer
124 views

Possible error in Hatfield's "Quantum Field Theory of Point Particles and Strings"?

In problem 8.1 of Hatfield's Quantum Field Theory of Point Particles and Strings, the reader is tasked with calculating the trace $$\operatorname {tr}(\gamma_0\frac{(\not p_2 + m)}{2m}\gamma_0\frac{(\...
Daniel Waters's user avatar
1 vote
2 answers
77 views

Conservation of kinetic energy and external forces

In Goldstein's "Classical Mechanics", at page 360 below eq. (8.84) it is stated that: "If, further, there are no external forces on the system (monogenic and holonomic), ..., then $T$ ...
Matteo Menghini's user avatar
0 votes
1 answer
64 views

Classical Theory of Fields: Energy-momentum tensor, error on page 80?

I'm trying to understand the physical significance/interpretation of the various parts of the stress-energy-momentum tensor. The book I'm using is The Classical Theory of Fields, by Landau and ...
John's user avatar
  • 824
0 votes
0 answers
44 views

Range of validity of geometric optics misstatement in University Physics

University physics claims in a discourse regarding electron microscopy that, Geometric optics is valid whenever interference and diffraction effects can be neglected And I struggle to interpret this ...
meltyness's user avatar
  • 131
1 vote
0 answers
155 views

Textbook solutions

I am trying to study quantum physics on my own time, and I have been using the textbook "Introduction to Quantum Mechanics," by Bransden and Joachain, as my guide. The book is great and very ...
slithy_tove's user avatar
1 vote
4 answers
261 views

Definition of Heat and the requirement of a different temperature - Zemansky

In Zemansky's "Heat and Thermodynamics", the concept of thermodynamic heat is defined as: $$ Q = \Delta U - W_{i \to f}^{dia}$$ where $\Delta U$ is the change in internal energy between the ...
Matteo Menghini's user avatar
3 votes
3 answers
332 views

Thermal Equilibrium and adiabatic walls - Zemansky

In Zemansky's "Heat and Thermodynamics" it is stated that: A thermodynamic system is in thermal equilibrium with its sorroundings iff it is in mechanical and chemical equilibria with its ...
Matteo Menghini's user avatar
1 vote
1 answer
274 views

Possible typo in Weinberg QFT when deriving the free fields

I'm going over some algebra in chapter 5 of Weinberg's QFT. On page 192 we have Lorentz invariance of the free field $$\tag{5.1.4} \psi_l^+(x)\sum_{\sigma n}\int d^3p\,\,u_l(x;p,\sigma,n)\,a(p,\sigma,...
Simplyorange's user avatar
0 votes
1 answer
48 views

Are the options correct of this question? [closed]

Q) An object is being pulled in the west with 50N force and in the east with 20N force. What will be the value of the net force? A) 53.85N B) 63.85N C) 43.85N D) 50.85N I feel that none of the options ...
tryingtobeastoic's user avatar
2 votes
1 answer
174 views

The Beta Function and the Bare Charge

According to "Introductory Lectures on Quantum Field Theory", by L. Álvarez-Gaumé and M. A. Vázquez-Mozo, (P. 84) the dependence of the bare charge $e_{0}(\Lambda)$ on the cutoff $\Lambda$ ...
Leonhard Leibniz's user avatar
1 vote
1 answer
116 views

Doubt in position operator acting on fourier transform, $\tilde{f}(k)$ of $f(x)$

I was solving a problem from the problem sets provided by MIT OCW. Here's the problem set. I was stuck in the problem 2(g) So, I looked at the solution to the problem and couldn't understand it. ...
Sumit Gupta's user avatar
2 votes
2 answers
272 views

Possible error in Griffiths, Intro. to Electrodynamics, Problem 7.60

Probelm 7.60 of Griffiths' Introduction to Electrodynamics, 4th ed, says: Suppose $\mathbf J(\mathbf r)$ is constant in time but $\rho(\mathbf r, t)$ is not—conditions that might prevail, for ...
Physor's user avatar
  • 870
3 votes
1 answer
363 views

Noether/Hilbert energy-momentum tensor

In chapter 4 of Carroll's book Spacetime and geometry he finds using the Hilbert action that the energy-momentum tensor for a scalar field is (see eq. (4.79)) $$T_{\mu\nu}^{\phi}=\nabla_\mu\phi\nabla_\...
Saoirse's user avatar
  • 186
0 votes
0 answers
105 views

Is there a bug in this step (and how to fix it?)

Reading an old book of classical mechanics (Spiegel's theoretical mechanics) I came across a passage that I would like to clarify. In order to find the equations of motion of free falling point ...
Fausto Vezzaro's user avatar
0 votes
0 answers
45 views

Baker-Campbell-Hausforff Formula: Is this an error in the book?

Possible Error: I am reading Quantum Theory of Finite Systems by JP Blaizot. In particular, chapter 4: Wick Theorems. I believe there is a typo in Equation (4.4), which in the textbook is $$ e^{A_n+...
Ivan's user avatar
  • 980
7 votes
5 answers
952 views

Does this question have two answers correct?

A simple pendulum (whose length is less than that of a second's pendulum) and a second's pendulum start swinging in phase. They again swing in phase after an interval of $18$ seconds from the start. ...
Righter's user avatar
  • 212
0 votes
1 answer
442 views

Induced e.m.f and the speed of the magnet. (A-Levels Physics)

When a magnet is moved into a coil of $50$ turns at $0.12$ m/s, an E.M.F. of $3.60$ V is generated into the coil. What will be the E.M.F. generated when the magnet is removed from the coil at $0.48$ m/...
godai yuusuke's user avatar
2 votes
1 answer
187 views

Inconsistency in Goldstein’s Lagrangians for Relativistic Point Particles?

In Goldstein’s Classical Mechanics (3rd edition), section 7.10 focuses on covariant lagrangians for point particles. Here, we begin by stating $$L=-mc\sqrt{x’_{\nu} x’^{\nu}}, \tag{7.162}$$ with ...
Nate MacFadden's user avatar
1 vote
1 answer
143 views

Kohn-Sham equations, Sakurai 3rd edition, possible typo?

In Sakurai's quantum mechanics book 3rd edition page 448, equation 7.88, the book writes "Kohn and Sham found a way to derive a self-consistent approximation scheme, based on single particle ...
Simplyorange's user avatar
5 votes
1 answer
303 views

Is there a typo in Carroll's expression for the Christoffel symbol transformation formula?

On Section 3.2 of Carroll's Spacetime and Geometry, he works on the proof of how Christoffel symbols transform under a change of coordinate system, in order to the covariant derivative of a tensor ...
Victor Lins's user avatar
6 votes
1 answer
441 views

Conformal Ward identities for local conformal algebra: error in textbook?

In Schottenloher's mathematically-oriented CFT textbook, "A Mathematical Introduction to Conformal Field Theory," Proposition 9.8 on page 160 states the conformal Ward identities for 2D CFTs ...
Daniel Ranard's user avatar
4 votes
3 answers
3k views

College Board Problem: Conservation of Momentum -> Conservation of Energy in a Spring

In my AP Physics C class today, we ran into a problem written by College Board whose answer we disputed. The problem is as such : A block of mass $M=5.0 \ \mathrm{kg}$ is hanging at equilibrium from ...
Sebastian Pojman-Malo's user avatar
2 votes
2 answers
335 views

Peskin and Schroeder equation 3.136 (book edition 1995) [closed]

I'm studying Peskin and Schroeder's QFT and I'm confused by equation 3.136 on page 68: $\textbf{Previously, on page 48, equation 3.62 says:}$ $\textbf{My question is: how do we deduce 3.136 from 3....
Simplyorange's user avatar
0 votes
1 answer
118 views

Possible erratum in Hartle's book "Gravity" in example 15.1

I'm reading Hartle's book Gravity (2014), and I think there's an erratum in example 15.1. In this example, he says that for a massive particle at infinity at rest, which starts falling radially ...
R. M.'s user avatar
  • 615
9 votes
3 answers
3k views

I Do Not Understand a Textbook Example: Calculating Voltage Across a Resistor

I am reading Agarwal and Lang's Foundations of Analog and Digital Circuits for self study, and I do not understand one of their illustrated examples (specifically, example 2.14). They present this ...
clo_jur's user avatar
  • 209
1 vote
1 answer
140 views

Why does Schwartz discard the product of counterterms $\delta_2\delta_m$?

In Quantum Field Theory and the Standard Model by Schwartz the author starts with the QED bare Lagrangian, defines $A_\mu^0 = \sqrt{Z_3}A_\mu$, $\psi^0 = \sqrt{Z_2}\psi$, $m_0=Z_m m_R$ and $e_0 = Z_e ...
Gold's user avatar
  • 36.4k
0 votes
1 answer
208 views

Approximation Methods in Physics

There is this one statement in my physics textbook that I didn't quite get for finding out how much change in the time period of a pendulum occurs due to a small change in its length, due to thermal ...
Destiny-wolf's user avatar
0 votes
1 answer
125 views

$\displaystyle{\not}{a}\displaystyle{\not}{a} = a^2$ or $-a^2$ in Srednicki

I'm confused: In Srednickis Book (Equation 37.26), he has: $$\displaystyle{\not}{a}\displaystyle{\not}{a} = -a^2$$ However, every other source I found (for example this SE question says that it's: $$\...
Quantumwhisp's user avatar
  • 6,773
2 votes
0 answers
71 views

Error in Hamiltonian of system in a paper

In this paper the authors investigate how work can be extracted from entanglement. However in section II under point 1. I think there is a mistake: They write that the Hamiltonian is $$H_i=H_i^A \...
eeqesri's user avatar
  • 1,488
4 votes
1 answer
8k views

What colors reflects the most infrared radiation?

About fifteen years ago I read in a book (Physics by James Walker 3rd edition) that dark brown color reflects IR better than any other color and consequently weather heat since our bodies get most ...
USER249's user avatar
  • 553

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