1
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2answers
55 views

Origin of the word Permittivity

Who coined the word "permittivity"? It appears that first usage was in 1887. Please cite your source.
2
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2answers
130 views

Why is the Faraday Tensor derived from the Lorentz force?

If we start from the Lorentz force, $$\textbf{F}=q\textbf{E} +q\textbf{v}\times\textbf{B}$$ and use the four velocity u$^{\mu}$ and the four momentum p$^{\nu}$, then we get to ...
1
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2answers
112 views

Terminology for line integral of magnetic field

One of the quantities appearing in the integral form of Maxwell's Equations is the line integral of the magnetic field around a closed loop. (The relevant equation states that this is equal to the ...
0
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1answer
234 views

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?
1
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1answer
128 views

How did neodymium magnets get their name?

Like in the question. Why neodymium magnets (Nd2Fe14B) are called "neodymium magnets"? Why not boron magnets? Or iron magnets?
2
votes
5answers
108 views

Is there a more scientific term for “obstruction of EM waves”?

When EM waves pass through things like rain and hail, they can be "obstructed" and bounced back or absorbed, rather than passing through. I'm conducting an experiment on this effect, and wondered if ...
2
votes
0answers
51 views

What name would you give to the method of approximating an arbitrary magnet with many smaller dipoles?

Let's say I had an arbitrarily shaped permanent magnet, with total magnetic moment $M_{0}$. Ways to calculate the magnetic field of this magnet include an analytic solution (if one exists), as well ...
0
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1answer
64 views

Reason for the convention about polarization states

I'd like to know if there is a special reason for limiting convention of polarization state to waves that can be split in just two components of equal frequency.
2
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3answers
442 views

What does physics study? [closed]

Wikipedia definition: Physics (from Ancient Greek: φύσις physis "nature") is a natural science that involves the study of matter[1] and its motion through spacetime, along with related concepts such ...
0
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0answers
175 views

What is the electric field part of an EM wave? Radiation field or the induction field?

Look at this image: I wonder if the electric field is from the induction field from a vibrating electron or the radiation field? If it is from the radiation field, as I suppose, than can someone ...
4
votes
4answers
1k views

Work done by the Magnetic Force

The magnetic part of the Lorentz force acts perpendicular to the charge's velocity, and consequently does zero work on it. Can we extrapolate this statement to say that such a nature of the force ...
1
vote
1answer
6k views

Is there a name for the derivative of current with respect to time, or the second derivative of charge with respect to time?

This measurement comes up a lot in my E&M class, in regards to inductance and inductors. Is there really no conventional term for this? If not, is there some historical reason for this omission? ...