Flux Definition and 1000 Threads

On pp. 459 of Dark Sun: The Making of the Hydrogen Bomb Richard Rhodes writes: He is talking about soft-x-rays in that quote. I understand that X-rays are massless so their weight is zero regardless of the density of the flux. Is this not correct? Is there a better comparison he could have...

Hi How do you get a photon flux per unit wavelength curve for solar radiation? My understanding of "per unit wavelength" is that the wavelengths within a very short range are fired at a detector. The range is then gradually changed to cover higher wavelengths. The values of flux measured by...

eletric flux and charge have same units ie coloumb is it a coincidence or some similarity exists btw these two? electric flux density D= εE is used for calculating flux ψ not E .why?(read tht it is done for practical reasons) please explain the practical reasons ,if any.

Why is it that the air gap flux density is flat topped at no load. What happens to it's shape when machine is loaded?

Hello people, I think the problem what I have is well known in experimental physics. Hope, somebody can helps me, thanks in advance. Here is: There is a source of neutrons with a flux of λ neutrons per minute, which you do not know and want to estimate. You open the detector for one minute...

I know that the electric flux is a scalar quantity, but the concept of the Electric flux seems to confused me. If the electric flux density is a vector quantity, how come the electric flux is a scalar quantity? For example, I have the electric flux density: D=20i+2j. Isn't it means...

How to calculate the visual magnitude of a star having only the flux of such star? The equation involves 2 magnitudes and 2 fluxes, corresponding to 2 objects a and b: ma-mb= -2.5log10\left( \frac{F_a}{F_b}\right) but I just have Fa and I have to obtain ma. Is it valid to take...

are both of the equations i posted flux equations. one of them is for a surface of a solid and the other is for a curve?

Homework Statement Homework Equations I know that flux is ∫∫F[r(t,s)]dotted[∂r/∂s x ∂r/∂t]dtds The Attempt at a Solution So I parameterized the equation y=x^2+z^2 as: x = s y = s^2 + t^2 z = t r(t,s) = [s, s^2+t^2, t] I take the partial derivative of r with respect to s and t and then...

Hi, I think my problem may be a little trivial however I have been stuck on it for quite some time. I have plots of flux density (Jy) versus wavelength in order to look at a particular forbidden line. I want to find the luminosity of the line, however as I am dealing with Jy [W/(m^2 Hz)] I do...

The Question A single phase transformer has the following rating: 120 kVA, 2000 V/100 V, 60 Hz with 1000 primary turns. Determine: (A) the secondary number of turns (B) the rated currents on the primary and secondary (C) The maximum flux (D) given a maximum flux density of 0.25 T, the...

hi there! I have a bit stupid question: Imagine a solid metal cylinder. We put a . Explain to me please the exact model of the direct current electric flux of the particles. Is there a "skin effect" when a direct current is in action ?

I was wondering if my understanding on Magnetic flux and Faraday's law was correct or not, is this okay? Magnetic flux is the number of lines in a magnetic field (Φ) Magnetic field strength (B) is the number of magnetic field lines over a given area B = Φ/A Other names for magnetic field...

Referring to following links, I would like to know whether Solar Radio is equal to Radio Flux or not, it seems that it describes Solar Radio in different format. Are they monitoring the same objects? Does anyone have any suggestions on what the different is between them? Thanks in...

Magnetic suspension and levitation is the caused by the flux trapping effect in superconductors.How does this flux get "trapped"? Another quick question- We link a magnet to a superconductor by bringing it very close to one ,until both of them start attracting and repelling. My question is...

Magnetic suspension and levitation is the caused by the flux trapping effect in superconductors.How does this flux get "trapped"? Another quick question- We link a magnet to a superconductor by bringing it very close to one ,until both of them start attracting and repelling. My question is...

I have an electromagnetic field with a Poynting vector that has the following form in spherical coordinates: $$\bar{P}(R,\phi,\theta)=\frac{f(\phi,\theta)}{R^2}\bar{e}_{r}$$ The exact nature of f(\phi,\theta) is not known. Suppose I measure the flux of this vector field by a flat area...

hey all, i've recently started studying electrostatics, and i have couple of question about things that i did not fully understand, and would very much appreciate if someone could set me straight. 1) how can a cube, with a single charge in the middle of it have a flux? don't the field lines...

Referring to following link about Solar Radio Flux, I would like to know more about Solar Radio Flux, is Solar Radio Flux different from Electric Flux? What is the major difference in term of properties of their fluxs? Does anyone have any suggested materials on what Solar Radio Flux is about...

Hello everyone. I am trying to translate the flux of a source observed by a telescope, in different units. In my case, I have the flux equal to counts/cm^2/sec in a given energy band (15-50 keV) and I want to translate this information in erg/cm^2/sec, in the same energy band Here you can...

http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_s05_qp_4.pdfHomework Statement 6b Homework Equations flux linkage = BA B=F/iL The Attempt at a Solution from my understanding, if B=F/iL , if the current is zero...

Homework Statement Consider a cylindrical vessel with cross-sectional area 1m^2 Derive the particle flux (1/4n\bar{v})Homework Equations I have the solid angle: \Omega = 2π(1-cosθ) The Attempt at a Solution I'm assuming that the solid angle represents the full area that the particles can...

Homework Statement Evaluate the surface integral \int_{S} \int \vec{F} \cdot \vec{n}\,dSwith the vector field \vec{F⃗}=zx\vec{i}+xy\vec{j}+yz\vec{k} . S is the closed surface composed of a portion of the cylinder x^2 + y^2 = R^2 that lies in the first octant, and portions of the planes...

The work done so far https://www.dropbox.com/s/qmfidqot3nttlw5/phpQd8GGH.png https://www.dropbox.com/s/xn4t5m2aleopwy7/phpldZ0KX.png Is the answer correct...

Deaar all good morning I am very interested to the flux in a slab of extrapolated thickness a, containing distributed sources of neutron. A I have an example in which the source is given as s(x)=S(x+a/2) where S is a constant and x distance from the center of the slab. You mentioned in one...

Homework Statement Im starting to read about the electric flux and gauss's law. I am reading two books, Serway and Schaums electromagnetics. The weird thing is that I'm getting different equations for the electric flux Serway says that the Electric flux ψ is ∫E ds = 1/ε ∫ρ dv =...

We define flux density as D= ε E right? or even ∇.D=ρ But I can't link the above with what is given in the wiki where they have used the symbol "phi" http://en.wikipedia.org/wiki/Electric_flux What is the difference between D and symbol "phi"? I would be really happy if you could...

Homework Statement (See attached diagram)--Note this problem was taken from Barron's SAT Physics Practice Test 1 #58 As the loop rotates, the induced voltage will be maximum at... a) 0 degrees and 90 degrees b) 0 degrees and 180 degrees c) 90 degrees and 270 degrees d) 180 degrees and 270...

Homework Statement Water enters a kidney through a tube at 10 mL/min. It exits through a 6-mm-diameter tube at 20 mm/s.What is the rate of change of mass of water in the kidney? Homework Equations m=vpa q=va After conversions to meters V=.02 Q=.000167 A=(pi/4)*.006^2 = .0000282...

The dominant energy condition is interpreted as meaning that no observer will see a flux of energy flowing at speeds greater than c. In this post I'm basically asking how to relate this concept of "speed of the energy flux" more precisely to the stress-energy tensor. If we start with dust...

Homework Statement Given a vector field A=(2x,-z^2,3xy), find the flux of A through a surface defined by ρ =2, 0<\phi<\pi/2, 0<z<1 Homework Equations ∇\bulletA? The Attempt at a Solution Can I use divergence method here? This is a closed surface correct? A cylindrical...

Homework Statement If vector A=(2x,-z^2,3xy), find the flux of A through a surface defined by ρ =2, 0<\phi<\pi/2, 0<z<1 Homework Equations divA? The Attempt at a Solution Can I use divergence here? This is a closed surface correct? Is this is a cylindrical wedge? Also do I need to...

Homework Statement http://smartphysics.com/Content/Media/Images/EM/03/h3_lineD.png charge density 1 = .00029 C/m charge density 2 = -.00087 C/m h = .116 m a = .094 m a) What is the total flux Φ that now passes through the cylindrical surface of height h=.116 m? Enter a positive number if...

I have for a while been trying to understand the setup of this equation in calculating the collision flux of a gas through a given rectangular surface of area A: Number of collisions in a time interval Δt is (\frac{N}{V})AΔt\int^{∞}_{0}v_{x}f(v_{x})dv_{x} where f(v_{x}) is the fraction of...

**I need Help calculating Electric Flux? Homework Statement "A 2.51 μC point charge is placed at the center of a cube with a volume of 7.27 m3. Calculate the electric flux through one side of the cube." Homework Equations Eflux = E*Surface Area The Attempt at a Solution I tried...

Homework Statement An infinite slab of uniform charge density ρ occupies the region -∞<x< ∞, -∞<y<∞, -d/2<z<d/2. Homework Equations Use Gauss' Law to calculate the electric field density for -∞<z<∞ The Attempt at a Solution D=εE. Using that, I just need to find D =...

This is a question that has kept me awake, trying to rationalise it: Current is rate-of-change-of-flux (or charge if you prefer, which is the same thing): i = dQ/dt Therefore, flux or charge is the time integral of the current. Q = ∫i dt Therefore, if you have a direct current, does...

The flux rule for motional emf can be stated as: d\phi/dt = -\epsilon I have some questions regarding this. 1) Should I find this rule intuitive? And secondly a proof of this rule is given in my book, which I have attached. I don't really understand the idea of the proof - is the idea to...

Homework Statement Homework Equations \phi = \vec{E} * A * d phi is the electric flux E is the Electric field from vector form A is the area and A = \pir^{2} d is the distance on the axis (x, y, or z) The Attempt at a Solution s1 = s3 = 0 *Since they are along the y-axis...

Homework Statement Let F(x,y) = ( P(x,y), Q(x,y)) be a vector field that is continuously differentiable along the closed smooth curve C : x2+y2 = 1. Moreover let -F(x,y) = F( -x, -y)≠ 0 and P(x,y) = -P(-x,y) and Q(x,y) = Q(-x,y). Determine all the possible values of the circulation...

I have constructed a formula to represent the neutron flux from a disc emitter through an aperture. I have got it down to a double integral of a form that I can't see how to evaluate. Mathematica crashes on this and I am not ready yet to give up and go to numerical solution. Does anyone know a...

"Flux in Through/ Out of Caps" Purcell Homework Statement I'm working problem 5.11 in Purcell's E&M book. It's about relativistic particles, and the eventual condition about angles at which the E-field lines are directed. The ultimate goal is to prove that tan(\varphi)=\gammatan(\theta)...

Is there a simple way of calculating photon flux density from the lumens produced by a fluorescent tube?

Homework Statement A 10 cm long, 1 cm diameter solenoid contains 500 turns of wire. A current that varies as I = 5Sin(100πt) Amps flows through the solenoid wire. Calculate the magnitude of the magnetic flux at the centre of the solenoid as a function of time using equation (1). Compare this...

Homework Statement The relationship between the current in an N-turn coil and the flux created by it is given as: \Phi = \frac{ai}{b+ci} Determine the energy stored in the coil when the current varies from 0 to I. Homework Equations W = N \int{i d\Phi} The Attempt at a...

Homework Statement Find the flux of the following fields: F_1 = xi + yj F_2 = -yi + xj across the following curve: The circle r(t) = (cost) i + (sint) j t is from [0,2pi] Homework Equations Flux = ∫F dot n ds = ∫M dy - N dx The Attempt at a Solution For F_1 I got: M = x =...

Homework Statement The monochromatic flux emitted from unit surface area of a black body is given by F_{\lambda}(T) = \frac{2h\pi c^{2}}{\lambda^{5}} \frac{1}{exp(hc/\lambda KT)-1} Wm^{-2}m^{-1} If the distance to star X is 620 parsecs, calculate: (a) the radius of star X, in...

Homework Statement A solenoid has a radius of 2mm and a length of 1.2cm. If the # of turns per unit length is 200 and the current is 12A, calculate the magnetic flux density at a) the center and b) the ends of the solenoid Homework Equations The biot-savart law: \vec{B} = \frac{\mu_0}{4...

This is more a theoretical question than a practical one. Basically I want to know if the formulas I arrive for the flux of a Toroid and a Solenoid are correct Leaving aside the integration part this is the basic formula for the flux \phi = BNA B = magnetic field N = number of turns of...

Homework Statement As shown in the figure below, potential difference V exists between two parallel plates(a,b) that have a small hole. Uniform electric field E and magnetic flux density B exist in the region above the plates, and are perpendicular to each other. The directionof E is parallel...