All Questions
Tagged with electric-fields electromagnetic-radiation
241 questions
2
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Heaviside-Feynman formula for electric field vs. Griffiths book formula
I am looking at the Heaviside-Feynman formula for electric field:
$$ \vec{E}(\vec{r},t) = \frac{q}{4 \pi \epsilon_0} \left[ \frac{\vec{e}_{r'}}{r'^2} + \frac{r'}{c} \frac{d}{dt} \left( \frac{\vec{e}_{...
- 303
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85
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Is it possible to create a small instance of a sprite?
Im a high school student hence have no experience,the phenomenon im asking about is TLE (Trans luminous Events) specifically a sprite. From what i know, sprites are formed due to excitation of ...
-4
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1
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How do em waves travell in space axis [duplicate]
To be straight with my question. Why do em wave produced by accelerating/oscillating charge travell in space as why don't they just stay stationary at a point.why do they move in space.however I think ...
- 1
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59
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When the magnitude of the electric charge changes with time
If I place the spherical charge at the origin of the coordinate space and change the magnitude of the point charge over time, the electric field wave from the origin is generated as a spherical wave ...
1
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2
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Lenz's Law vs. Radiation Reaction: Does the change in the induced magnetic field produce an induced electric field?
Suppose we have a uniformly charged nonconducting ring. An induced magnetic field with a pattern perpendicular to the ring's plane will show up if it starts to rotate mechanically around the axis that ...
- 2,774
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2
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53
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In a superconducting LC circuit, is some energy dissipated in the creation and destruction of the magnetic or electric fields?
Quite simply, I'm imagining a pure LC circuit with zero resistance, current oscillating positive and negative, energy oscillating between the capacitor E-field and the inductor magnetic field. Is ...
- 55
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EM waves and electron waves
If electrons are also waves then how can they produce EM waves when they "jiggle" due to temperature rise
- 29
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2
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Why are oscillations in electric and magnetic field in EM waves said to be “perpendicular”?
My understanding is that the oscillations in EM waves don’t have a physical shape, like the squiggly waves you see when you shake a rope, but are actually just variations in the magnitude of the field ...
- 11
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1
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94
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Derivative wrt retarded time
I am confused by the following statement in footnote of Griffiths 4th edition (page 446):
$$\frac{\partial }{\partial t_r} = \frac{\partial }{\partial t},$$ where $$t_r=t - \frac{\mathscr{r}}{c}$$ ...
8
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7
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Is it impossible to construct a Faraday cage that can block a *static* electric field?
I think the answer is yes. My reasoning is this: Imagine for argument's sake, we could have a charged negative source that has its field blocked by a Faraday cage. We can transport a positive charge ...
- 10.2k
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0
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Why is the intensity of a beam of light the squared magnitude of the phasor and not just the squared magnitude of the real part?
I'm learning about phasors and light intensity and there are two conflicting things I've been told that I can't reconcile.
Firstly I've been told that a phasor $e^{-ikz+i\phi}$ is a mathematical way ...
- 531
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2
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134
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Why In an electromagnetic wave both electric and magnetic waves are in sync and perpendeculare? if one makes the other shouldnt there be a delay? [closed]
Why are electric and magnetic waves in phase if one induces the other? Shouldn't there be a delay, similar to how potential energy converts to kinetic energy and vice versa? Additionally, why are ...
- 21
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1
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75
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Is $\vec E$ more effective than $\vec B$ and why?
While reading about the Poynting vector in Optics (5 ed) by Eugene Hecht, I found the following line in page 42, from chapter 3.
Since, as we have learned, $\vec E$ is considerably more effective at ...
- 23
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1
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Why isn't the original EM wave in a beam of light in a medium not still detectable from a distance as if it were moving at the speed of light?
I'm learning optics and I've been told that the reason light slows down in glass is because the Electromagnetic field of a beam of light interacts with and accelerates charged electrons in glass ...
- 531
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2
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65
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Are all recursive interactions between electric and magnetic fields always orthogonal to each other?
ecursively, this implies that changes in the electric field generate the magnetic field, and vice versa, akin to the plane wave solution resulting from specific boundary conditions intentionally ...
- 53