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1:10 AM
Q: Curl of electric field

pasaba por aquiRelated: How is the curl of the electric field possible? According to my information: $$\nabla \times \frac{\hat{r}}{{|\mathbf{r}|}^2} = 0 $$ for all $\mathbf{r}$ ( including $\mathbf{r}=0$; compare with $\nabla \frac{\hat{r}}{{|\mathbf{r}|}^2} = 4 \pi \delta(|\mathbf{r}|)$ that is zero excep...

2 hours later…
3:12 AM
Q: Conservation of momentum in photon-atom collision

GoPhysIs this explanation correct: When a photon with the appropriate energy hits an atom, the electron will make a transition from the ground state to a excited state. This will make the potential energy of the atom higher. Also, momentum is conserved, and the velocity of the atom will change in the ...

14 hours later…
5:05 PM
Q: Earth magnetic field space elevator. No cable

Alexander SpacelifterI have an idea that the space elevator can be build in the following conditions: Not a classic theory. No cable. No Geostatic orbit. Not equator platform position The position is north magnetic pole - Antarctica. The lifting force is Earth magnetic field. The lift design is a huge ring (more th...


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