According to https://www.osti.gov/servlets/purl/7234564, the HERMES III which stand for High Energy Radiation Megavolt Electron Source accelerator is "capable of delivering a peak dose of ~100 krad (CaF2) over a useful area of ~1000cm2 (area where dose is greater than 50% of the peak dose) in a...
I am new to this forum, and this is my first post. Please bear with me if my query has any inaccuracies.
In the attached figure, a coil is wrapped around the central arm of a flat H-shaped thin metallic plate (such as iron). DC current flows through the coil and magnetizes the arm. At the...
This question is given as an exercise in my book. I can't figure out whether this is a poorly worded question or if I misunderstand. The answer I can come up with is that power is dissipated over the load so more power is needed to be supplied by the ac source. This seems too hand-wavy to me...
Summary:: need to increase the wavelength of light.
I am an intro physics student working on a project and need to increase the wavelength of photons. I only have visible light sources available but need to have an emission of a wavelength larger than 1mm. is there a way to shift wavelength...
I'm finishing up physics 2(intro E&M) at my college, and I'd like to apply the concepts I learned in it over the summer. I was considering working through an electronics book, or building a radio, etc.
What kind of projects or books do you recommend to cement some of the topics I learned in a...
Homework Statement
I was working out problem 4, chapter 3 of Introduction to Electrodynamics by Griffiths:
a) Show that the average electric field over a spherical surface, due to charges outside the sphere, is the same as the field at the centre.
b) What is the average due to charges inside...
A uniform beam of positively charged particles is moving with a constant velocity parallel to another beam of negatively charged particles moving with the same velocity but in opposite direction separated by a distance d. Then, how should be the variation of magnetic field B along a...
We know that "plastic" and "glass" charges were arbitrarily assigned to be negative and positive respectively, and electrons and protons were given their charges based upon that assignment (According to Randall D. Knight in Physics for Scientists and Engineers). I am curious if any significant...
Hello all,
The second quantization of a general electromagnetic field assumes the energy density integration to be performed inside a box in 3D space. Someone mentioned to me recently that the physical significance of the actual volume used is that it should be chosen based on the detector used...
Homework Statement
A monochromatic plane wave with wavelength 500µm is propagating through a dissipative medium with refractive index 1-0.0002i. It approaching the edge of the medium, and will pass out into free space. If the angle of incidence is not 90°, how much will the wave deflect as it...
I’ll be taking the year long physics sequence at my college this fall and I want to know what specific math topics I should master, so that I can conquer my first year of physics. I’m planning to brush-up on any necessary topics from algebra, through precalc, and including calc 1. It’s an honors...
I am trying to understand why an accelerating charge emits radiation/electromagnetic waves but a uniformly moving one does not. I saw one video on Youtube where it seemed that it was explained by the fact that with a uniformly moving charge the Poynting vector was pointing 'in to the volume' -...
I'm talking hotter than T = 6000k.
The higher the temperature, the more the curve in the attached figure would shift to the left (while at the same time getting higher).
So the intensity peak would eventually fall back into the invisible portion (very small wavelength this time) of the...
Hi, I have some confusion about the jump conditions for an electric field across an interface between two materials with different properties. In general, we have the two jump conditions across an interface:
n.(ɛE)+ - n.(ɛE)- = σ...
I was doing the calculations for this: http://fermi.la.asu.edu/PHY531/cylinder/index.html
But I can't figure out how to go from \frac{d\sigma}{d\phi} to the total cross section. My guess was that you did the integral from \phi=0 to \phi=2\pi, but that's not helping since I can't tell either how...
Homework Statement
A solenoid of volume V, current I and n turns per unit length has an LIH core, relative permitivity is \mu_r. This core is then slid out so that a fraction f of the solenoid's length is filled with air/vacuum (and 1-f is filled with the core).
Neglecting hysteresis, what...
It is a well known fact that, in electromagnetic units, strength of a shell and strength of current flowing through its boundary are same. See here.
\begin{equation}
\begin{matrix}
\text{i.e.}\: i \text{(biot)} = \phi \text{(biot) }
\end{matrix}
\tag{1}
\end{equation}
(a) While converting to...
For example, if I have a magnetic field perpendicular to some surface and I change this magnetic field with constant speed, how do I calculate the Electric field at any point on this surface, since ∫E⋅ds=k, where k is some constant, could be done with many different vector fields.
I am reviewing Jackson's "Classical Electromagnetism" and it seems that I need to review vector calculus too. In section 1.11 the equation ##W=-\frac{\epsilon_0}{2}\int \Phi\mathbf \nabla^2\Phi d^3x## through an integration by parts leads to equation 1.54 ##W=\frac{\epsilon_0}{2}\int |\mathbf...
Homework Statement
Initially there is a spherical charge distribution of with a radius ##R_0## and uniform charge density ##ρ_0##. Suppose the distribution expands spherically symmetrically such that its radius at time t is ##R_0 + V t##, where V is the velocity. Assuming the density remain...
Hey everyone
Just a picture of my configuration.
The assumption here is $$\epsilon_a,\epsilon_b,\epsilon_c$$ are different from one another. Really the interest of this problem is to find the scalar potential $$\phi$$, such that $$\nabla^2 \phi = 0$$.
So now my question, about jump...
I'm working on induction at the moment, and the math makes sense, but Lenz's Law is giving me trouble. Does anyone have an easier way (relatively) of remembering the directions of emf? Any advice is appreciated.
Is there a theory that explains the mechanism under which photons exceeds the speed of light?
It should refer to cases including photons generated in an oscillating charges, dipoles, inhalations, different kind of excitation, accelerated particles, scattering phenomenons etc.
Please note that...
Homework Statement
Suppose electrons enter the electric field midway between two plates at an angle θ0 to the horizontal, as shown in the figure, where L = 5.1 cm and H = 1.1 cm. The path is symmetrical, so they leave at the same angle θ0 and just barely miss the top plate. What is θ0? Ignore...
[Moderator's note: changed thread title to be more descriptive of the actual question.]
Consider Maxwell's action ##S=\int L## over Minkovski space, where the Lagrangian density is ##L = -\frac{1}{4}F_{\mu\nu}F^{\mu\nu}##, and the Electromagnetic tensor is given by ##F^{\mu\nu} = \partial^\mu...
Homework Statement
Two coencenteric metalic shell has inner radius $r_1$ outer radius $r_2$. We place along axis infinity wire has $\lambda$ charge in per unit length. The inner region of metalic shells inserted with relative permabilitty coefficent $\epsilon$. This system rotates with $\omega$...
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Hello! I have a question on Electromagnetics.
Could anyone check if I am on the right track?
Here is the proposed problem:
Consider a spherically symmetric current distribution, which is radial and...