The total force on a charge is equal to $\mathbf {F}=q\mathbf {(E+ v×B)}$ where everything have their usual meanings . We can say that: $$dW= \mathbf {F\cdot dl} = {\mathbf{F}\cdot \frac{d \mathbf{l} }{dt}} dt= \mathbf {(F\cdot v)}dt = q(\mathbf {E\cdot v})dt = \mathbf {(E\cdot j)} dt ...... $$ ...

Why do charges exist, how did they come into existence? (if any theories exist, then please explain them in somewhat detail) What would happen if charges never existed? Please explain the answers at the scope of an 11th standard student Thank you

In Stein & Shakarchi's Fourier Analysis, the Fourier transform of a Schwartz function $\psi$ is defined to be $\hat{\psi}(\xi) = \int_{-\infty}^\infty \psi(x) e^{-2\pi i x \xi} dx$ which gives the uncertainty principle as $\Big(\int_{-\infty}^\infty (x-\overline{x})^2|\psi(x)|^2 dx\Big)\Big(\int_...

This is a follow-up question after this one: Yes, the curvature is enough to bend lasers. In fact, there is an interesting feature in Schwarzschild spacetime that might answer your question well. but in principle you can arrange light to orbit the black hole indefinitely. I should add that this...

In optics, we usually consider a non-magnetic medium where the magnetization $M$ is zero, while the polarization P is proportional to the electric field $P=\epsilon_0\chi E$. $P$ is induced by some microscopic dipoles with dipole moment $p$. These dipoles would align with the electric field's dir...

I need to have a fully functioning understanding of entropy so I've got a few questions to ask What are the conditions for an increase in entropy to be reversible? I (think) I know that any process where the temperature is constant is assumed to be reversible, but what other constraints can I p...

I am wondering if anybody has ever calculated the odds of a rogue planet, which has been travelling through interstellar space and then enters into a galaxy, actually reaching the massive black hole at the center of that galaxy. I would think that the odds of a rogue planet reaching the black hol...