1. ### Calculating flux with a magnet and a coil

Homework Statement [/B] Hey, I'm having some difficulties with my physics project and I hoped someone could help me out. We have to calculate the magnetic field, but first we need to know the flux. This is the setup we got: We have to let a magnet fall through a PVC tube. The tube has a coil...
2. ### I Calculating the flux from a flashlight

Can you use the flux-luminosity relation, f=L/4*pi*d^2 to calculate the flux of a flashlight at a distance d? As I understand, we can use the relationship given above for a star since we assume that it emits radiation uniformly in all directions, we take the total energy emitted and then divide...
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### A Determine the flux of the vector field trough the surface

From my drawings it seems to be half of hemisphere. Am I right? How can I solve this task? Determine the flux of the vector field $$f=(x,(z+y)e^x,-xz^2)^T$$ through the surface $Q(u,w)$, which is defined in the follwoing way: 1) the two boundaries are given by \delta...
4. ### I Particle calculation during a solar proton event

Trying to figure out how many particles would bombard an astronaut during a solar proton event. Given that the most possible is around 43,000 particle flux units (pfu) according to NASA. First calculating steradians, assuming a person is 1m^2, 1/(1E9)^2=1E-18. My calculation yields (43000...
5. ### A X-ray tube flux and my experimental test setup

Hi everyone! I'm starting to work with a mini X-ray tube provided by Amptek. I want to use it to calculate the efficiency of a detector i'm going to use latter, so knowing the total flux the tube emmits and measuring the flux the detector receives, that should be enough (both data normalized to...
6. ### Flux of the Poynting vector

I have some problems in calculating the flux of Poynting's vector through a surface. I have that: S=c/4π⋅H^2⋅n (S: Poynting's vector, n: versor of the direction of the propagation of the em wave) H=1/cR A' but: A=(1/cR) d'; A'=(1/cR) d'' ==> H= (1/cR)^2 d''...
7. ### Backing-out luminosity togo from lumens to radiant flux in W

Hi. Has anyone already done the work to back out the standard luminosity function so I can go from lumens at a particular wavelength to radiant flux in Watts? I have visible LED spec sheets with optical characteristics in lumens and I want to calculate the outputs in W. My NIR LED has specs in...
8. ### Why is the flux through the top of a cylinder zero?

This is example 27.2 in my textbook. I have the answer, but it doesn't make sense to me. I understand that if electric field is tangent to the surface at all points than flux is zero. Why, though, does my textbook assume that the ends of the cylinder don't have field lines extending upwards and...
9. ### Model of how temperature depends on latitude?

Homework Statement I was asked to 'Use a very simple model to find how the Earth’s temperature should vary with latitude.' Homework Equations The Attempt at a Solution I was thinking about flux and how this should be proportional to the temperature. So I first thought about the area that is...
10. ### Magnetic flux density calculation for high permeability material

Hi to all of you, As the Biot-Savart-Law is based on experimentations in air, i like to know how to calculate the magnetic flux density in material with much greater permeability, where the circular like shape of the field distribution troughout the vicinity does not apply. Does anyone has a...