# All Questions

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### Components of gravity in an inclined plane

The reason the block accelerates down the inclined plane is that the resultant of $N$ and $mg$ acts down the incline. However, why is the force causing the block to accelerate down the incline often ...
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### Why does a ball eventually stop?

I was wondering, if the force of friction with the ground does not make any work on the ball and just give it the necessary torque to rotate (hence the consideration of static friction coefficient in ...
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### Dark energy and magnetic field

I have learned that a photon creates it's own magnetic field. Arno Penzias & Robert Wilson discovered the background radiation from the Big Bang. Could this also be the time of the creation of ...
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### What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
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### Rotation operation on spin-1/2 particles

How does rotation operators work on a particle? What does it do on the particle conceptually? Also does particles spin on its axis?
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### Unified Theories

How can a unified theories help us? Like after unifying electromagnetic and gravitational forces will there be some ease on how we study forces? PS: This is my first SE post.
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### What will happen to a man if he hangs from the power cable of train using one hand and secondly using two hands?

If a man holds and hangs from the power cable of trains with one hand, will he be alive or will he die if he holds and hangs from the electric wire using two hands without touching the ground ? I ...
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### Maximum uncertainty in position of ground state in infinite square well

Could somebody please explain to me this statement: "In a square box of total width L we have L/2>Δx, with the value L/2 arising in the limit in which the wavefunction would peak symmetrically ...
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### Solve for emf in the circuit

The ammeter is the circuit reads 2.0 A. What is the unknown emf?
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### Where is the net electric field 0?

A positive charge +3Q is separated by a distance, d, from a negative charge -Q. What is the closest distance in which the net electric field is zero.
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### Creasing of a material at the molecular level

What exactly happens when a material (particularly paper or even cloth or a metal) is folded to form a crease? Why is it that a creased material tends to retain form, while a lightly folded one, ...
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### S-matrix and derivative interaction

I just read in some lecture notes that formally we can write the S Matrix as: $$S=T(e^{-\int_{-\infty}^{+\infty} H_{int}dt})$$ Where $T$ is the normal product and $H_{int}$ is in the interaction ...
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### what is the effect of temperature on the resistance of a photoconductor?

As we know, for a photo conductor resistance tends to decrease with increase in irradiance, but with greater irradiance comes greater temperature. Also we know, photo conductors are ...
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### Why do some people support more electricity than others?

There is a game where people hold by their hands and two of them touch the electrodes of a shock box, then an electric current flows through them. I understand that since they are all making a single ...
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### Question on weightlessness

An astronaut in an artificial satellite of the earth feels weightlessness. Do they feel weightlessness on the moon too? Why? An astronaut in all artificial satellite feels weightlessness due to the ...
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### Based on newtons third law

If an elephant can apply 250N force and a rabbit can apply 25N force , and if they are pulling each other , then elephant will pull with 250N force and according to newtons third law the rabbit should ...