Confused Definition and 1000 Threads

I've written in that only the first statement was False, however my classmates aren't getting the same answer? Please help clarify...

I am not entirely sure if I solved this problem correctly. Please let me know if my reasoning is flawed. Thank you and I appreciate your help greatly.

I am still so totally confused about the ultimate source of the photons of the CMB. I am getting really confused by online sources, who are either not very clear, or seem to contradict each other. I feel like I have narrowed it down to two sources; 1. The early universe was full of high...

I am just confused on what the comma means. Can someone explain what each value would be or the explanation?

This is a very elementary question, from the beginnings of quantum mechanics. For simplicity, I refer to a finite case with pure states. If I understand correctly, the spectrum of an observable is the collection of eigenvalues formed by the inner product of states and hence equal to...

What I mean is the way that a product of cosines in which the angles increment the same amount is equal, with some extra terms, of the sum of the cosines. It is discussed here...

The first two parts to the question were as follows. If a vector field ##\xi## preserves the Maxwell field then ##\mathcal{L}_{\xi} F = 0## so by Cartan's magic formula ##i_{\xi} \mathrm{d}F + \mathrm{d}(i_{\xi} F) = 0##. But since ##\mathrm{d}F = 0## then ##\mathrm{d}(i_{\xi} F) = 0 \implies...

The problems I am referring to are problems 4-10 and 4-11. There is no solution provided for 4-10, so I want to check my answer here. However, I don't understand the answer to problem 4-11. Shouldn't it also be 24 V since it is in parallel with the 200 k##\Omega## resistor? I am actually...

Hello! I thought that in spontaneous emission (say for an atom with 2 energy levels) we have the electron in the excited state and then it decays to the ground state emitting a photon at the resonance frequency. However I saw the attached figure, which introduces Mollow triplet. I understand the...

So for this question I got the right angular velocity. But I don’t get the same velocity for point A. I don’t understand why it’s cos30, problem asked for V_a when theta = 45 so I used cos45. I have my work below.

I am a little confused with the concept of proper time: Using the invariance of the distance square in the Minkowski space, we can get the expression ##d \tau = \frac{d t}{ \gamma}## Now the problem: Aren't the proper time the time measured by a moving clock? That is, if i am moving with speed...

Hi - i am confused about the following basic mechanics principles Consider a large cubic mass ( mass M ) on the ground with a small cubic mass ( mass m ) placed on top of it. The surface between the 2 masses is frictionless 1 - if a push (apply a force ) to the large cube does the upper...

Hello! Assume we have a 2 level system, with the ground state defined as the zero energy level and the excited state having an energy of ##\omega_0##. If we apply an oscillating electric field (assume dipole approximation and rotating wave approximation) of frequency ##\omega##, we have a time...

So the textbook uses 3 equations for these, d 2/dt2 (y1 + y3 − √ 2y2) = − k / m (2 + 1/ √ 2 ) (y1 + y3 − √ 2y2) d 2 /dt2 (y1 + y3 + √ 2y2) = − k / m (2 − 1/ √ 2 ) (y1 + y3 + √ 2y2) d 2/ dt2 (y1 − y3) = − 2k / m (y1 − y3) Now the question is asking for the largest natural frequency. Now I...

Im confused as finding the minimum value of lambda is an important part of the proof but it isn't clear to me that the critical point is a minimum

Hello! Assume we have a 2 level system with the frequency between the 2 levels ##\omega_0## and ignore the lifetime of the upper state. In order to measure the transition frequency using Ramsey technique, you apply 2 ##\pi/2## pulses separated by a time ##T##. We have that the probability of...

I came across a derivation of the Noether theorem with a step I don't understand; the transformation of the time and configuration space are written as$$\tau(t,\varepsilon) = t + \varepsilon \delta t, \quad Q^a(q,\varepsilon) = q^a + \varepsilon \delta q^a$$here ##\varepsilon## is an...

All I'm reallly confused on this problem is what the expression for the emitted field is. As long as I've got that, I'm good to go, but I just don't know what to use. I've tried looking for an expression for the emitted field but I've had no luck. Would appreciate any ideas or someone telling me...

Like I said, objects with the higher acceleration are giving me the lowest values. For a hoop, I got I=0.1*MR^2 For a cylinder, I got I=0.7*MR^2 this seems backwards, no?

We can find the difference of time to light reach both clocks, it should be Lv/c², what i am confused is why the rear clock show a higher reading of the front clock. Ok, the light take longer time to travel and reach the rear clock, and here is the thing! What i am interpreting is: When the...

I'm confused on how De Broglie's hypothesis works. I've attached my thinking in a pdf file below. I'm not an expert in the field of particle physics(I'm only in high school), so there may be some error in my logic(I really think so, or else De Broglie was wrong!(hint:he isn't)) I've also read...

This confusion has lingered in the back of my mind for years now, would be good for me to finally get a grasp on this. Say I have an object currently at rest, and I use energy X to accelerate it to speed v. According to the standard formula, it now has a kinetic energy 1/2mv^2. Now I use the...

Here's a diagram of the object My Question: My friend and I were solving this problem. We both found Fxnet and Fynet. However to find work I did W= Fnet*d whereas he did W= Fxnet* d. He claims that since it's sliding on the floor it can only go in the x-direction, and it can't go in the...

Question 1; a. sin θ=√3/2 θ=arcsin √3/2 θ=π/3 rad sin √3/2=60 degrees 60 degrees *π/180=π/3 rad. To find the other solutions in the range, sin θ=sin(π-θ) π-π/3=2π/3 The solutions are π/3 and 2π/3 in the range 0 ≤θ ≤2 π b. cos2θ=0.5 2θ=arccos 0.5 2θ=π/3 rad Divide both sides by 2; θ=π/6 rad...

Hello! Let's say we have 2 states of fixed parity ##| + \rangle## and ##| - \rangle## with energies ##E_+## and ##E_-## and we have a P-odd perturbing hamiltonian (on top of the original hamiltonian, ##H_0## whose eigenfunctions are the 2 above), ##V_P##. According to 1st order perturbation...

Question 1; a) P=E/t E=5.796*10^7 J energy produced per day during the summer However, I am not certain how to calculate the time period, since although this concerns the energy produced per day, the sun does not shine for the entire duration of this 24 hour period. Also, I am unsure of the...

Hello! Can someone explain to me in an intuitive way (or a nice mathematical demonstration) or point me towards some accessible papers about the AC Stark effect (Autler-Townes effect)? I am mainly confused by how can one start from a 2 level system (consider a 2 level system for simplicity) add...

Hi. I understand that the number 20, written like this, has 1 significant figure Suppose I took a pile of measures of length: 18, 19, 20, 21, 22, 23, 24, 25 giving a mean of 172/8 = 21.5 on my calculator If I have to give the mean to the lowest number of significant figures then that would...

The figure shows two mercury barometers. 1. My first question is why specifically does it have mercury? Is the mercury a gas or a liquid? Why can we not just use water? Does the pressure of the liquid have to be less than that of the atmosphere for this to work? 2. The book says for a given...

Angular velocity is the degrees by which something rotates over a time period. If I have an angular velocity in one direction and I resolve it into its components, its components would obviously be of lesser value. Here's what I don't get. When I imagine this scenario, I see that the thing...

I am thinking that this circuit needs to be simplified somehow? Finding an equivalent resistance and moving from there?

Hello! I am a bit confused about a resonance signal that is obtained by measuring the fluorescence signal from overlapping a laser beam with some atoms. Based on the signal shape, the maximum number of counts corresponds to the resonant frequency of the transition (ignoring for this questions...

I do not know where to start.

For a double integral, we might treat the "inner integral" separately and be able to compute something like ##\int_{x_1}^{x_2} f(x,y) dx## by holding ##y## constant during the integration. The same technique is applied in other places too, like for solving exact differential equations. I haven't...

I think the answer should be## c = (300,000,000 ~meters/second) ## ## 300,000 km = \frac {300,000,000 ~ \rm{m/s}} {1000 ~\rm{km}}## ## d = vt ## ## d = 40,075 km ## ##t = \frac d v#### 40075 km / 300 000 km/s =0.1336 s ## Why is the answer 7.5? An help appreciated

I'm confused about how to find the final value of g and its uncertainty. I've done a bit of research and I have encountered conflicting information, some say you have to weight the measurements, some say you have to find the standard deviation then divide by two, etc. I have the following...

Looking at. <psi|AB|theta>, under what conditions would this be equal to <psi|A|theta> * <psi|B|theta> I’m just getting into perturbation theory and am running into confusing notation. Thanks john

94% * 91% * 91% = 78.8% how does this becomes like that?, I m havig the result of 778414

$$c'\begin{pmatrix}u \\ v \end{pmatrix}=\begin{pmatrix}\frac{\partial f^1}{\partial u} & \frac{\partial f^1}{\partial v} \\\frac{\partial f^2}{\partial u} & \frac{\partial f^2}{\partial v}\end{pmatrix} $$ There is a problem with the first line of the matrix, but I am not too sure what it is.

Hello all, I remember a story from late 2014, when I watched a gameshow "Who is he/she?" This gameshow requires panel judges (often composed of celebrities) to guess which is the fake person with specific occupation (such as barber) out of three possible candidates present to them. In an...

For passive electrical components, I can understand the need for the passive sign convention - i.e. taking the voltage to be the potential on the side where the current enters (higher potential, for a passive component) minus the potential on the other side. For a resistor, this means the change...

well I was watching the Third Season, and I was Confused, there's an esper her ability name is Float Dial it is an ability to control buoyancy. at first I understand, that it controls fluids thus able to slide on water walk on walker. but how the does she able to lift the heavy concrete and...

Hello! I am reading Introductory Nuclear Physics, Second Edition, by Samuel Wong and in Appendix B-3, he talks about the effective range. In the derivation of the formula, in equation B-34 he writes: $$v_0(k,r)=_{r \to \infty}u_0(k,r)=_{r \to \infty}=A\sin(kr+\delta_0)$$ where ##v_0(k,r)## is...

Hello, I've searched a bit about about the thermal radiation behavior of non-black body and I'm confused. I've read that the color is dependent only on the temperature so every thing display the same color as a black body. But at the same time I've read that materials don't always follow the...

I know how to solve ODEs using both methods. The problem I'm having is knowing when to use one and not the other. If someone could help clarify this for me. I can't find the correct section in my textbook.

I've learned that ##W = -\int{P_{ext} dV}##, and only during a reversible/quasi-static process where ##P_{int} = P_{ext}## can we write the work done on the gas in terms of the internal pressure (and consequently use ##PV=nRT## etc. which apply to the internal gas). However, a lot of sources...

Hello! In the (famous) plot I attached we have the branches ratios for the Higgs decay for different Higgs masses. I am sure that sitting down and doing the Feynman diagram calculation (to 1 or 2 next to leading order?) I will get these curves. But I am a bit confused about the physics intuition...

The question says: A solution of highly acidic HA is given, with a molarity of 1M. Is it true that [A-]>[H3O+] or not? I simply don't understand why the hydronium is mentioned and i don't know how to find the molarity of these two individually.

I am sorry if these questions are basics, but I am not sure I totally understand the basics of how a laser works and the books I read are not totally clear for me, so any explanation would be greatly appreciated. So assuming we have a plane mirrors cavity and a gain medium in between, we create...