All Questions

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Quantization of electric charges [on hold]

As per charge quantization of charge $Q=ne \Rightarrow n=Q/e$. But there can exist some charge $Q$ such that $n$ isn't an integer (i.e if $Q/e$ is repeating or recurring decimal). This can prove ...
807 views

How does the heat death looks like from inside the system?

As this answer points out, any human would first freeze rather than experience the heat death. However, assuming hypothetically that we could make some robot live at such low temperature (or even ...
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Laser diode input and output power ratio [on hold]

I am a photo technician working in photographic labs to repair printing machines. I need technical help from you and from your technical team, as I want to know some basic information. May be it will ...
63 views

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Does the uncertainty principle affect event horizons? [duplicate]

I was thinking about black holes. For a simple black hole the event horizon is given by a distance of 2 times mass (energy) of the black hole. (2m). But according to quantum mechanics, if you try to ...
43 views

Why is the net work done in a pulley-string system zero?

In any pulley system, where the pulleys and strings are massless and frictionless, why is the net work done by Tension zero?
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Effect of orbifolding on gauge fields

A paper by Lalak et al, entitled "Soliton Solutions of M-theory on an orbifold", considers the brane solutions of 11 dimensional supergravity on a space of the form $R^{10} \times S^1/\mathbb{Z}_2$. ...
1k views

Can we know if “all” physical laws are discovered?

Before Einstein, scientists believed that all physical laws to be discovered were already discovered. Of course, that was proven wrong. If we somehow manage to come up with the Theory Of Everything ...
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Is a non reflective display possible?

Can you think of a surface, that emits light, but doesn't reflect any light coming from outside (absorbs it)? Under what circumstances would this work?
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solving an electromagnetic problem in the frequency domain

I study a course in electromagnetic fields and I don't understand why when I solve a problem in the frequency domain I lose the transient solution. can anyone show me mathematically why does it ...
37 views

What exactly is 'crosses of light'? [on hold]

when i looked two bulbs through my window it appeared as luminous crosses.i also took photoes.what exactly is this?
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The relation between mass and speed

Massless particles (or luxons) have no (rest) mass ($m = 0$) and a speed equal to the speed of light ($v = c$). Massive particles (or bradyons) have mass ($m > 0$) and a speed lower than the speed ...
921 views

Do electrostatic fields really obey “action at a distance”?

In an electromagnetic theory class, my professor introduced the concept of "action at a distance in physics". He said that: If two charges are at some very large distance, and if any one of the ...
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How can electric and magnetic fields have any component in the direction of propagation of electromagnetic waves?

In case of waveguides we talk about E and H having non zero component in the direction of propagation of wave. But the entire basis of EMW is that E and H are perpendicular to the direction of ...
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Could the fundamental dimension of Electric Charge be Mass only? [on hold]

If true what would it mean for physics.
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Suggest a material used in a specific product that can be improved by alternatives? [on hold]

such as the beverage cans, what materials can be used to replace the current packaging technology? or any other types of future development that may take place in the packaging technology? What other ...
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Charge enclosed by a Gaussian surface inside an uniformly charged thin sphere [duplicate]

Why is the electric field due to a charge enclosed by a Gaussian surface inside an uniformly charged thin spherical shell, zero?
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Free rotation of a rigid body

So I am currently reading Fowles and Cassidy and there is something I'm confused about in the section about geometric description of free rotation of a rigid body. I will present the stuff first that ...
28 views

Circular motion physics [on hold]

Two automobiles of equal mass approach an intersection. One vehicle is travelling with velocity 13.0m/s toward the east and the other is travelling north with speed V. The vehicles collide at the ...
88 views

Can space be destroyed [duplicate]

Wikipedia says It appears that space was created in the Big Bang, 13.8 billion years ago This seems a little off to me: can we say something has been created if there was no before it had ...
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What is the kinetic energy of a proton as it is falling towards the core of the star?

Given: Star's mass = $1.99e10^{30}kg$ Type II supernova occurs (in a simple form: the outer layers of the star fall into the now inactive core at speeds of 126000km/s) $10^{44}$ joules of energy is ...
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Speed as the fifth dimension

In spacetime there are four general dimensions, three of space and one of time. Why is it that other dimensioned qualities seem to be rarely considered as part of spacetime? For example, why isn't ...
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Does a graviton impart negative momentum?

Picture a massive system on an axis. If a graviton is generated and emitted by a system in the positive direction, will that system also be accelerated in the positive direction? Another system ...
28 views

How to know if a body is travelling with uniform acceleration or not?

One of the Example in my Textbook is A body travels a distance of 2 m in 2 seconds and 2.2 m in next 4 seconds. What will be the velocity of the body at the end of 7th second from the start. In ...
45 views

Understanding the Carnot cycle

My textbook explains the Carnot cycle as follows: Heat is added to the boiler, where the steam inside expands isothermally at high temperature (T(High))--(both valves closed). The intake valve is ...
21 views

Torque-direction of rotation

Taking moment about $A$, the mass of 2.0g and 0.50g is rotated in the clockwise direction is because they are both directed in downwards position? while $R2$ is acted in upward direction, so it is ...
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Maxwell said the dimension of charge is $L^3 T^{-2}$ and of mass is $L^3 T^{-2}$, is he right? [on hold]

If his right then, from Lorentz magnetic force, $$F= BQV$$ where $F$ is force, $B$ is magnetic flux density, $Q$ is charge and $V$ is velocity. Therefore, $$M L T^{-2} = B Q V \, .$$ Substituting for ...
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Is the proton mass to charge ratio equal to the plank mass? [on hold]

Using a proton charge 1.602*10^-19 coulombs is equal to proton mass 1.673*10^-27 Kg. One coulomb = 1.673*10^-27 Kg divide by 1.602*10^-19 Therefore One coulomb is equal to 1.044*10^-8Kg. Therefore ...
59 views

Is gravity weak negative electric charge? [duplicate]

This could be true since the both have infinite range and other common properties. They both have fields.
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Can two artificial bodies be built in space and be made to orbit each other?

Would it be possible to make artificial constructs (satellites) orbit each other? I looked at the gravitational laws, and nothing seems to suggest that this is not possible.
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Can the anti-torque of a motor be used to spin a space vehicle about it's axis?

Imagine a huge electric motor together with it's power supply in space. What exactly will happen to it if it is suddenly powered, won't it spin about it's axis or it will experience no relative motion ...
48 views

Why does transmission probability decrease, increase, then decrease again?

We did a quantum tunneling lab online. We used a Java program to model the electron wave function and show what happens when there is a step potential (U is less than E). Our value for the ...
50 views

How is light slowing down in a medium thought of in the photon picture? [duplicate]

The speed of light in any medium besides vacuum is smaller than $c$. In a classical way, I just look at that as a wave that propagates less fast, the change in EM-field is passed on slower. How should ...
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Is the Legendre transformation a unique choice in analytical mechanics?

Consider a Lagrangian $L(q_i, \dot{q_i}, t) = T - V$, for kinetic energy $T$ and generalized potential $V$, on a set of $n$ independent generalized coordinates $\{q_i\}$. Assuming the system is ...
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How do the renormalization enter the actual amplitude calculation in QFT?

I have studied QFT from Peskin and Schroeder and from a few other books and lectures and I think I understand the procedure of renormalizing various parameters in the Lagrangian like mass, coupling ...
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Mass and wave function renormalization In chiral perturbation theory

Before I put forward my actual question, I think it will be useful to set the context in a clear way and that involves my understanding of a few very basic things of Chiral Perturbation Theory. ...
198 views