Watching this pretty great video from 1947 about antenna fundamentals. I have a question about one part of it though. The video states that the impedance at the feed point of the antenna is 72 ohms, which they say is determined by comparing the energy dissipated by the antenna to the energy dissi...

My question arises from studying section 8.1.3 of Sakurai. I am confused on the way Klein–Gordon equation is created. In Sakurai, the book said that it was derived by taking another time derivative to the Schrodinger equation to obtain a covariant derivative form (as explained in equation 8.5 and...

Consider the earth body excluding the atmosphere, undergoing circular motion around the sun. Does it experience air resistance due to the atmosphere?

I am studying formalism of QM from the book by Griffiths. He illustrates via two examples that momentum and position operators have no eigenfunctions in Hilbert space. In that case, how can we expand a general state vector (in Hilbert space) in position/momentum eigenbasis, as the eigenvectors co...

With Compton scattering the total momentum and the total energy of the photon electron system is conserved, so it has to be ELASTIC Collision/Scattering. But an argument is that just because the kinetic energy of the incoming photon is different than the outgoing photon, it is INELASTIC Collision...