# Search results

17. ### Best Way to measure Relativistic Rocket Acceleration?

Someday, mankind will be able to construct rockets that can move at relativistic speeds. The acceleration is given by $a=\frac{F_0}{γ^3m_0}$ $F_0$ can be easily measured by placing a force gauge on the rocket itself. The acceleration is much harder to measure, is has to be measured in a...
18. ### I How was Kramer's Law derived?

Kramer's Law describes the spectrum of Bremsstrahlung radiation: How did Kramer derive this formula?
19. ### I For Dummies Derivation of Radiation Pressure>Energy Density?

The formula for the radiation pressure P in n-dimensional space for a given internal energy density u is $\frac{u}{n}$. I would really appreciate it if someone could provide a link that gives a simple derivation of this formula for dummies like me.
20. ### I Breakdown of Planck's Law under certain Conditions

The difference between Planck's Law and the Rayleigh-Jeans' Law is, in Rayleigh Jeans, the average energy per mode is $kT$, whereas in Planck, it is $\frac{hc}{λ(e^\frac{hc}{λkT}-1)}$. These average energy formulas are multiplied by another formula to give either Planck's Law or the...
21. ### I SR Doppler Effect: Differences in Wave VS Momentum Models

In his seminal paper on Special Relativity: On the Electrodynamics of Moving Bodies, Einstein derives a formula for the Relativistic Doppler effect. See this section: § 7. Theory of Doppler's Principle and of Aberration The formula is: In this Wiki article, the same formula is derived. The...
22. ### I How are Vectors described in Bispherical Coordinates?

I was reading a paper that described a vector field in terms of its three components , $A_σ,A_τ,A_φ$. with σ, τ and φ being the three bispherical coordinates. what does $A_σ$ mean? In what direction does the component point? Likewise for the other two components.
23. ### I Field Lines of an Electric Dipole?

It isn't difficult to find the electric field of a dipole. However, it is tricky to find the field lines. All points of a field line have to be parallel to the electric field at those points. A tangent, which is the derivative, is parallel. We can hence formulate the equation for a field line...
24. ### I Electric Field Between Two Metal Balls.

Imagine you have two identical metal balls, each carrying the same amount of charge, but with one ball being positive and the other negative. When you bring them close together, there will be polarization, so you can no longer treat the balls as point charges. How does one find the charge...
25. ### I Lorenz Curves and Distributions...

Is it correct to say that the Lorenz curve is the normalized integral of the quantile function with respect to the x-axis?
26. ### I Inverse of Maxwell-Boltzmann Distribution and Planck's Law?

I'm looking for the inverse functions of the Maxwell-Boltzmann distribution and Planck's Law. Planck's Law in terms of the wavelength. Any of you know of any literature on this topic?
27. ### I Help me Integrate this function

I would like to integrate w.r.t. x, the rest are constants. This is not homework; it is related to a physics problem regarding single-slit diffraction.
28. ### I Does a Magnetic Moment μ exist for any closed current loop?

I'm asking the above question as I imagined a current loop made out of a curving wire that cannot fit into a flat plane. Where does the direction of μ point then? Also, is there only one μ value for any current loop, independent of the chosen axis of tilting? Or can a current loop have...
29. ### I Finding the Electric Field of a Hollow Cylindrical Conductor

I am trying to find the electric field of a hollow, open-ended, thin-walled cylindrical conductor. I am trying to solve something regarding LINACs: Assume we have an isolated, hollow, open-ended, thin-walled cylindrical conductor, with a net charge. The net electric field within the...
30. ### I Zero-Divergence of Rate of Change of Magnetic Flux

Let's introduce a time-varying scalar field ρ(x,y,z,t) [charge density] and vector field J(x,y,z,t) [current density] Assuming the system follows Maxwell's equations, what must both fields satisfy such that $∇⋅(\frac{∂B}{∂t})=0$ ?