Difference Definition and 1000 Threads

Well my question is what is exactly the difference between Astrophysics and Cosmology and Quantum mechanics ?

Hello Forum, Consider a simple DC circuit composed of a battery (say 2V), conducting wires and a single resistor R=2 Ohm The potential difference across the resistor will be exactly 2V only if the wires were superconductors (zero resistance). But wires do have some small finite resistance so...

When an neutrino is observed, it becomes a point particle, but it has mass. Is that mass not concentrated into a point? Why doesn't it collapse down to a micro black hole? What's the difference between a neutrino and a micro black hole of the same mass? I know it has 1/2 spin and other...

1)I am confused why do we take vectors along y-axis and x-axis in motion on a plane? What's essence of learning vectors functions. 2)And in textbooks, they have given that motion in a straight line has 2 directions only. Hope many do motion on a plane has? Please give me simple and detailed...

At some point in the history of technology something happened whereby some devices that operate by electricity became known as "electronic" devices while others remained merely "electric" devices. The latter are obviously simpler, but it's not clear to me where the cut off between the two should...

Hi All A mathematical structure : is A set with an Object ( structure ) and there are generally two types of mathematical structure , which are algebraic structure and space ( geometric structure ) Eaxmples of algebraic structure are rings , fields , modules vector spaces ... act Examples of...

Hi PF! I was wondering if anyone could help me with a finite difference question? The problem I am doing is a 1-D space and time problem, so ##z## (space variable, from left to right) and ##t## (time) are my independent variables and my dependent variable is ##h##, the height, governed by a PDE...

So what is the difference between the two? Special Realitivity and General Relativity.

...real science and corporate backed bias. I've been having a debate over several issues with a, well he works for the same company, but we don't see each other, so I don't know if I should call him a coworker or not. He refuses to do any fact checking, one recent thing (about 5 mins ago) he...

What are the differences and pros/cons of each?

Hey! How are the two m=0 spin states (<up,down> + <down,up>) and (<up,down> - <down,up>) physically different? I realize that according to the math, the first one has a total spin of ##2 \hbar## while the second has a total spin of ##0##. But wouldn't you, intuitively, expect both states to...

I know that manifolds are topological spaces that locally look like euclidean spaces near each point of and open neighbourhood And non-euclidean spaces are the curved spaces or simply don't match the 5th euclid's axiomThanks .

Homework Statement So i was in a course yesterday and the "teacher" told us the following (which i had a hard time believing/understanding) There is a load connected to a transformer. Applied potential difference is 230V. The load is malfunctioning and the insulation isn't working anymore. The...

Notion of differentiability (analyticity) for function of complex variable is normally introduced and illustrated by comparison with function of single real variable. It is stated that there are infinite number of ways to approach any given point of complex plane where function is defined, not...

Homework Statement A conducting sphere of radius a is surrounded by a neutral conducting shell of radius b (b > a).Connections are provided as shown in diagram. Initially, the sphere has a charge Q. The switch S1 is opened and then closed. The switch S2 is then opened and closed. Finally, the...

I know the two steel grades: M2 tool steel and 1.3343 steels are similar. But the M2 has Mn element while 1.3343 has W elements. what would be the differences with such elements ?

Hello, recently I became interested in some basics of material science and there was one thing that I did not really understand. What is the difference (or what are things in common) between creep and strain rate sensitivity? I read about it in connection with indentation. - To measure the...

Q6c) Why is the phase difference between two points in a stationary wave equals to zero? I understand that a stationary wave is formed by two progressive waves which have the same amplitude, frequency, wavelength and speed, but traveling in opposite directions.

Hello, How do I take into account the difference in stiffness when fabricating a part (for example, an L-bracket) from sheet metal or using an extrusion? In particular, where I work, it is "common knowledge" that extrusions are stiffer. How do i factor this in the stress and strain...

Hello everyone..I have some difficulties in understanding the potential difference in a circuit with a transistor. Kindly refer to the picture provided. I understood that potential difference across Ry can be obtained from the formula in the picture. The potential difference across Rx plus Ry...

In case of power transformer,what is the difference between electrical fault and thermal fault? I want to know that if internal fault is occurred in power transformer then on what basis we can differentiate electrical and thermal fault?

Hey guys, I have a problem that I really have no idea what to do. It was discussed in class that we do not need to know how to integrate or use the dot product-- any of the complex stuff. 1. Homework Statement The electric field in a given region in space is given by (3 i - 1 j) x 10^5 N/C...

Homework Statement If 3000V is applied to the teltron tube with EHT voltage, what would be the potential difference between the parallel plates in the teltron tube? Homework EquationsThe Attempt at a Solution Since one end of the plate is positive, the other end is negative, 3000V-(-3000V)=6000V

Homework Statement Homework Equations V=IR W=VQ The Attempt at a Solution The answer is B, though I thought that electric potential difference is the ratio of energy to charge? Why is the answer stating the ratio of energy to current instead?

Obviously there are MANY differences, but I'm curious about one in particular. In an article I read, the creator used NiMH batteries because of their high charge density, but also because they do not require a charge controller and voltage regulator in the circuitry. Why is this, and is there...

The question is based on the image below but is not the same. The question is as follows: Assume the capacitor is charged, so that there is a charge q on the top plate and a charge -q on the bottom plate. Determine the magnitude of the potential difference across the k2 region, answering in...

what is electric potential?and what is the difference between electric potential and potential difference?

This has been causing some confusion to me as the two concepts seem very similar, if not the same (especially when taking special relativity into account). As far as I understand, even in classical physics (i.e. even before considering QFT and the like), one requires that interactions are...

Sorry... This question may be very basic. As a self taught, I understand that the mass will bend the space around it such that any other mass entering the bent space will immediately be pushed towards the center because of the bent space. Higher the mass, higher will be the bent (if that is the...

A plant cell is usually larger in size. An animal cell is comparatively smaller in size. 2. It cannot change its shape. An animal cell can often change its shape. 3. A mature plant cell contains a large central vacuole. An animal cell often possesses many small vacuoles. 4. Plastids are present...

I understand that Contravariant vectors have an upper index and co-variant vectors use a lower index. But why is one preferred over another in a specific physical situation? I am just struggling with which form is preferred, and why one would bother trying to raise or lower the index in a...

Hi all, I am confused about the terms: Vibration, oscillation and waves. Is vibration and oscillation same or are they different? My understanding is vibration is associated with flexible/deformable bodies and oscillation for rigid bodies. Waves not really having an idea! Any examples of...

I am hesitant to write this post. I am a bit overwhelmed that many members have questions of a higher level. They may be reading scientific journals. My question is very basic. I might be called stupid. Coming to the question. Is angular momentum same as spin of an electron?. But I read that...

I am looking over the supplies on University Wafer until I notice the following: link: https://order.universitywafer.com/default.aspx?cat=Borofloat%2033%20Glass&diam=100mm They sell quartz, fused silica and Borofloat glass as different products. I thought quartz and fused silica are the same...

Hello I have a quarter wave plate for 550 nm but i can't determine which it is a zero quarter wave plate or multiple. How can I find m in this formula : delta phase =m*2 Pi +Pi/2 ? Thank you.

Homework Statement How would i go about finding the electric field and potential difference when there is a constant charge density between the capacitor rather than a vacuum? Homework Equations int E dot dA = Qencl/epsilon0 V ab = int E dot dl The Attempt at a Solution to be honest I am not...

Homework Statement Is there any difference between these 2 terms, if yes how are they different? \begin{align}(\nabla\cdot\nabla\vec A)\vec B &= (\nabla\vec A\cdot\nabla)\vec B\end{align} Homework Equations From what i know about dot product, it is commutative, so does this property apply here?

I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sinkis a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And the...

I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And...

Gravity causes spacetime to warp. Relative speed also causes an apparent warp from the point of view of the stationary observer. But warp due to relative speed will cause rods to contract, rods will effectively measure shorter for the stationary observer. Accordingly we should also infer that...

Difference between Calculus 4th edition and Calculus 3rd edition by Michael Spivak? I currently possesses Calculus 3rd edition by Michael Spivak in it's electronic form. However, I am considering buying a hard copy and have the option of buying either a used 3rd edition or a new 4th edition...

what is difference between abs(1/x^2) and 1/x^2 . i am using https://graphsketch.com/ graph result is same. what do you think?

what is the difference between a normal circuit with transistors and resistors and the integrated circuit?

A difference matrix takes the entries of a vector and computes the differences between the entries like [x1 - 0 ] = difference from 0 and x1: 1 step [x2 - x1] = difference from x2 and x1: 1 step [x3 - x2] = difference from x3 and x2: 1 step assuming we had a vector x in Ax = b So why now when...

I'm new to quantum physics, and this might be a stupid question. What is the difference between Photons and the Higgs Boson? I know that neither of them interact with the Higgs field. And that when CERN found the Higgs Boson, it decayed into other particles INCLUDING photons. So what's the...

I have a container with one inlet and one outlet. I have the area of the inlet, Ai, velocity vi of the air coming in, and mass flow mi (assume a plane with an air inlet to a bay). I don't know anything about the outlet (just that there is one). What I need to do is calculate the size of an extra...

Inside a conductor, as opposed to inside an insulator, charges are free to move around and reposition themselves, which causes that, if we wait a long enough time, the electric field inside them will be zero. But in an empty space there's nothing (by definition) that can stop charges from...

At first, we need some state parameters(like P/T/V) to fully describe a system. And the order parameter is also a parameter which could describe the property of the system. However, in the Laudau theory, why it said that order parameter is an external parameter(not a independent variable)? Is...

On the wiki-pages it says that in the LHC protons travel 3m/s slower than c. I was curious what it would be for heavy-ions; is it maybe 15m/s because their energy is ~5 x lower (7 vs. 2.76 Tev) ? And a small question on the side, does Gravitation assistance have a bigger impact on speeding up...

whatis the difference between flat and thin plates?