Tag Info

New answers tagged

1

The fast electrons slow down in the cathode, mostly due to interactions with atomic electrons. But hard X-rays are produced mostly due to deflection to large angles in the field of atomic nuclei. Roughly speaking, an atomic electron can stop the projectile electron in a head-on collision, but a nucleus can "reflect" the projectile back, so here the ...


1

The change in velocity of the electron give rise to emission of X-rays. The electrons arrive at the anode with very high velocity and end up at thermal velocities - which must mean they slowed down. Both statements are therefore true.


2

When a charged particle comes into the vicinity of another, it's path is deflected. It decelerates in one direction, and accelerates in another. All charged particles that are accelerated/decelerated by another charged particle, or a magnetic field, emit radiation. See: Bremsstrahlung. Synchrotron radiation. Cyclotron radiation.


2

The electron does not move - it has no well-defined position in the orbital state, and hence no well-defined momentum. Neither does it "teleport" around - as long as it is not interacting with something that forces it to be at a definite position, its state is "smeared" all over the electron as an electron cloud. Yes, this is essentially the Bohr model, ...


0

Once the gammas are produced, they do not carry particular information. There is just a certain probability, measured by a differential cross section, that, if they scatter again, they produce $e^+,\,e^-$ as in the initial pair.


0

Suppose a conductor with cross sectional area $A$ has $n$ mobile charge carriers per unit volume, each carrying a charge $q$, which moves through the conductor at an average drift velocity of $v_d$. Now the total charge in a segment $\Delta x$ is: $\Delta Q = (nA\Delta x)q$ Now, the charge carriers moving at an average drift velocity of $v_d$ will move a ...


0

The minimum uncertainty says that ΔyΔP_y = hbar/2, where Δy is half of the width of the slit, and ΔP_y will give you the linear momentum in the y direction. If you divide ΔP_y by the mass m of the electron, cca. 1-^{-27}gr., you get Δv_y, the velocity in the y direction, ( equal to minus velocity in the -y direction). To get the width of the pattern on the ...


0

Edit after rereading the quesiton. Agree that it is (all else being equal) easier for electrons to travel down a wire with a greater cross sectional area. (Not sure why this is not intuitive - for me it is easier to walk down a wide pavement than a narrow passage between two buildings - particularly if other people are about to provide some 'resistance' - ...


1

To start with the electric field of the electron is as far as possible to measure symmetric, the electric dipole moment is very small. In this article The electron's EDM must be collinear with the direction of the electron's magnetic moment (spin). Within the standard model of elementary particle physics, such a dipole is predicted to be non-zero but ...


1

In a Fermi-Dirac distribution, the relationship between temperature and the speed of particles is not intuitive. Even at cold temperatures, fermions can have high speeds simply because of degeneracy - the lower momentum states "fill up", leaving only states with large momentum available, and this is true even at very cold temperatures. However, the heat ...


1

If you think about the infinite square well problem, the states with higher energy have higher momentum, (and also a higher velocity). However, it is better to think of the higher energy states as higher frequency standing waves. Because they have a higher frequency, the have to "travel faster", which is where the large velocity comes from in the Fermi ...


1

The probability of atomic excitation by photon absorption is given in terms of the "cross- section" for single photon absorption. This quantity shows a sharp peak if the photon energy and the atomic energy level difference match (the coupling between the atom and electromagnetic field causes the atomic states to broaden, the natural line width). Thus ...


0

Current is basically the flow of charges.Well what i think so whatever charge it is it will flow and will cause the production of current and if there is a production of current electricity is automatically formed.For example the current positron generator.Here is a link where there is a PDF which is all about Dirac current generator ...


4

You are being imprecise about electricity. It's probably better to just think of electricity as current. You have a current whenever you have a charge moving. To your question, yes, positrons are just as good as electrons for carrying a charge. There is no difference between "positron electricity" and "electron electricity". Another way to see this is ...


2

The electron on an atom gets excited to a higher level when some how the energy is transferred to the electron. But I can't understand it. The way we currently understand in physics this interaction is exactly like that: a photon transfers its energy to the atom and as a consequence one of the electrons goes to a corresponding exited state. And this can ...


4

Be careful to compare the same quantity. You ask if gravity (a force) affects the voltage (a potential energy). These are related but not identical. For a first round comparison, check out the forces due to gravity and a standard voltage (1 Volt over a distance of 1 cm): First, the gravitational force on an electron at the surface of the Earth: $$F_g = mg = ...


1

The rationale is this: Assuming that $x$ and $x'$ are random vriables Their variances are given as $\left<\Delta x^2 \right>$ and $\left< \Delta x'^2 \right>$ Now the covariance of both $x$ and $x'$ is different if $x$ and $x'$ are correlated as random variables or not. If they are not correlated the covariance (joint correlation) is just the ...


1

You are right, it happen due to circular motion. This effect is called Thomas precession. In 1925 Thomas relativistically recomputed the precessional frequency of the doublet separation in the fine structure of the atom. He thus found the missing factor 1/2, which came to be known as the Thomas half. There are several method to derive it. For example one ...


0

when we apply magnetic field to any ferromagnetic substance and remove it , small fraction of magnetic strength remains. for completely demagnetize it, an opposite magnetic field is needed this magnetic field is called coercivity of the material.this is different for different materials. coercivity is low for iron, so that it demagnetize easily and it is ...


-3

No collision is possible in between two electrons because the electron carry negative charge and push each other away with some assumption


0

An electron in a homogeneous magnetic field $\vec B$ has only 2 possible spin states, typically called 'spin up/down'. These two states do not refer to the total spin being perfectly aligned/anti-aligned with $\vec B$. The total quantized angular momentum is $S=\sqrt{3}/2\hbar$ while the z-component is $S_z=\pm1/2\hbar$. Thus the state of precession with ...



Top 50 recent answers are included