All Questions
28
questions
0
votes
1
answer
77
views
Why can you equal $e\times U=\frac12 mv^2$? [closed]
When calculating the accelerating voltage to accelerate an electron to a certain speed, we usually use the following equation:
$$e\times U = \frac{1}{2}mv^2$$
But why does this work? On the left ...
- 13
0
votes
1
answer
140
views
How do I show that the total energy of a particle moving in an electrostatic field is constant?
Basically the Lorentz force says that:
$$F=qE+qv × B$$
I am asked to show that if a particle moves in an electrostatic field
$$E= - ∇V(x,y,z)$$
and ANY magnetic field, then the energy:
$$\frac{1}{...
0
votes
2
answers
10k
views
Electromagnet Electricity Consumption?
Wikipedia states that -
The only power consumed in a DC electromagnet is due to the resistance of the windings, and is dissipated as heat.
Is this true? So powerful magnets like junkyard magnets ...
- 251
6
votes
3
answers
1k
views
What would it take to cause lightning to jump between the Moon and the Earth?
This question comes from @Floris' speculation at the end of his excellent answer about what it would take to kill everyone on the Earth with electricity.
Doing all this in 1/10th of a second requires ...
- 4,534
2
votes
0
answers
492
views
Motion of a charged particle in a "solid" charged sphere (accounting for radiation)
Consider a particle (point charge) with charge $q$ and mass $m$ that crosses into a uniformly charged sphere (with charge $Q$ and radius $R$). The trajectory of the particle is a diameter of the ...
- 31
0
votes
3
answers
148
views
Traveling to Mars in 24 Days
I am trying to calculate an electromagnetic rail launch from the Moon but I need to know if humans can survive the launch. Please see the specs below.
150 miles of track
Proposed final launch speed ...
- 13
0
votes
1
answer
2k
views
Equation of Trajectory [closed]
I was reading about Lorentz force law and motion of a charged particle under Electric field or magnetic field and I understood how they move in it.
But as I was moving further I came across the ...
- 343
1
vote
2
answers
423
views
Description of the motion of the COM of a system of charged particles moving in a magnetic field
I recently came across a problem where an electrically neutral particle is at rest in a uniform magnetic field. The particle now splits into two charged particles of equal mass $m$; charge and mass ...
- 2,077
0
votes
2
answers
610
views
Electrical force between two objects
I tried to solve the following problem:
There are 2 objects . The object m1 with charge q and the object m2 with charge q.(same charge).The object m2 is connected with a rope to the ceiling.
at the ...
- 397
9
votes
1
answer
860
views
Electron in the proximity of a magnetic monopole
I am puzzling about an exercise in the book "Electromagnetic Theory" by Ferraro (p.543).
An electron (mass $m$, charge $-e$) in a monopole magnetic field $\vec{B}\left(\vec{r}\right)=g\frac{\vec{r}}{...
- 393
0
votes
1
answer
6k
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A basic question: what is accelerating voltage? [closed]
Or would it be acceleration voltage? Acceleration sounds like it makes more sense, but my paper says accelerating.
What are possible ways you could go about calculating it?
- 103
1
vote
2
answers
789
views
Movement of the particle in a magnetic field
This is the numerical question.
A particle having a mass of 0.05 mg carries a charge of $5\times10^{-6}C$. The particle is given an initial horizontal velocity of 5000 m/s, what is the magnitude ...
- 2,565