Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 22717

The classical theory of electric and magnetic fields, both in the static and dynamic case. Also covers general questions about magnets, electric attraction/repulsion etc. Distinct from electrical-engineering.

0 votes

electromagnetic waves dependence on frame

In the frame of the particle you just see a constant electric field. From outside this field must change as the particle moves by. Just have a look at this.
  • 1,580
0 votes

Electric and Magnetic Field Intensity Analogy

I agree with Lucas Francisco that $H$ is an auxiliary field, but in vacuum one could, e.g., write $$\frac {1}{ 2} \mu_0 H^2,$$ which, for symmetry reasons, looks much better with respect to the elect …
  • 1,580
0 votes

Magnetic field of radially emitted alpha particles by a sphere of polonium

The Maxwell way First I assume that the current is homogeneous. In that case the important point to realise is that if current goes away, the sphere becomes charged. If the total current going away i …
  • 1,580
0 votes

What determines the magnitude of force of an electromagnet?

As @Uncle-Al said, it depends on shape distance etc. I remember, however, a standard exam question. Assume you have the electromagnet with area $A$ and you want to lift an object that can be magnetize …
  • 1,580
4 votes

Cylinder , charge on surface, why is B inside zero?

Just for picturing it...meaning this is not exact: If you are not in the middle, where it is clear, but close to one side you may see it like this: the length over which you see a wire approximately s …
  • 1,580
1 vote
Accepted

Why is a paramagnetic material attracted into a magnetic field?

I think there is some confusion here. The actual field direction does not play a role for diamagnetic or paramagnetic behavior. What is important is the field strength. What is actually ment by Griffi …
  • 1,580
1 vote

energy of eddy current with increasing frequency

In detail eddy currents are very complicated and a 100% answer might not be possible. First of all, it should be clear that the efficiency will not be greater than 100%. The Eddy current is taking en …
  • 1,580
2 votes

Shooting a bullet into an MRI

New Version (as I had my doubts on the orders of magnetude...and it turned out that I made a mistake) To simplify things I assume: velocity $v=1000\; \mathrm m /\mathrm s$ perfectly conducting bull …
  • 1,580
1 vote

intuitive explanation of $E \times B$ drift with constant and perpendicular $E$ and $B$

For intuition I would like to simplify the continuous circular motion piecewise into four sides of a square: the electric field accelerates the particle in $y$-direction to velocity $v_1$ the magnet …
  • 1,580
1 vote

Will a hollow ferromagnetic core for a solenoid yield any benefit as opposed to a solid meta...

A thin wall tube can have a significant effect on coil performance. Unfortunately, for hollow core cylinders analytical solutions only exits for $\lim \mu_\mathrm{r} \rightarrow 1$ or better say $\lim …
  • 1,580
1 vote
Accepted

How does mu-metal affect magnetic fields?

The thicker the mu-metal the more the flux will return inside your horse-shoe construction. The inner field will increase for the following reason: you may think of this in terms of magnetic charge. F …
  • 1,580
2 votes
Accepted

Currents in circuits

Switching on and thinking in the $\mathrm{d}/\mathrm{d}t$ properties of $C$ and $L$ means that the resistance of an inductance is basically infinity and that of a capacitance is zero. For long times t …
  • 1,580
6 votes
Accepted

Magnetic levitation frog example

Yes, the frog will be repelled from the field if the field is non-uniform. Its magnetic moment is given through the susceptibility of Water $\vec \mu = V \chi \vec H$ and $\chi_\mathrm{water}\approx …
  • 1,580
0 votes

How to calculate Centripetal force of a helical movement inside a magnetic field?

Your formulae are correct. The movements are comletely independent like in an inclined trajactory of a thrown ball where $v_x$ and $v_y$ are independent: one is constant ,the other affected by acceler …
  • 1,580
1 vote

Potential energy from opposing magnets repelling each other with a gap of 1 mm

If you bring two magnets together in such a way that they repel each other, you store potential energy $E_\mathrm{pot}$ . This is correct. The force will be the according derivative $F=-\mathrm{d} E_\ …
  • 1,580

15 30 50 per page