2d
awarded  Yearling
2d
answered Does ionization process release energy?
Jul
16
comment Does ionization process release energy?
@JohnRennie Yes, but the point is that after the first ionization, the remaining electron isn't in a state from which it can decay to a lower energy level, so the emission event that OP expects simply never happens. I think I'm just repeating what you said a different way, but I'm hoping it addresses OP's confusion more directly.
Jul
16
comment Does ionization process release energy?
@CangYe A helium atom in the ground state has two electrons, both in the 1s orbital, so when you knock one of them out with a photon, the other one isn't affected (as the most probable outcome). The effect you're looking for would only be seen if the helium atoms were already in an excited state (in which case it might be very hard to distinguish from background decay to the ground state), and in heavier elements, where at least one electron has to be in a higher orbital even in the ground state.
May
18
comment Why is there no current between two capacitors connected in series?
@MohammadAlshareef I think you're clinging to the notion of there being an absolute zero for charge. There isn't. Zero in a circuit like this is defined by convention. Usually we choose the negative plate of the battery to be zero. Then the potential at the capacitor terminal connected directly to the negative plate of the battery will also be zero. The potential at the other terminal of that capacitor will be higher than that, and the potential at the far terminal of the other capacitor will be even higher (and equal to the potential of the positive plate of the battery, in this case).
Apr
18
awarded  Popular Question
Mar
22
answered Strong empirical falsification of quantum mechanics based on vacuum energy density
Mar
11
revised If sound is a longitudinal wave, why can we hear it if our ears aren't aligned with the propagation direction?
added 381 characters in body
Mar
11
comment If sound is a longitudinal wave, why can we hear it if our ears aren't aligned with the propagation direction?
Hmm, you've made me realize I drew my diagram wrong. I should have made the wavelength be much larger than the size of the hole. And I think I understand now what's missing from Wikipedia's explanation of diffraction. Thanks.
Mar
9
answered If sound is a longitudinal wave, why can we hear it if our ears aren't aligned with the propagation direction?
Jan
29
comment Can an atomic nucleus contain both particles and antiparticles?
N.B. from the links in the duplicates, it appears that there are short-lived $p\bar{n}$ and $\bar{p}n$ bound states, so the answer to "Would the strong force cause attraction ..." is yes.
2018
Dec
2
comment Why can we distinguish different pitches in a chord but not different hues of light?
@Yly Emil is correct; the cochlea does the Fourier transform, mechanically. See cochlea.eu/en/cochlea/function
Oct
26
comment Isn't the velocity in an orbit always tangential, not radial and tangential?
The overall velocity vector can always be equal to its component perpendicular to the line between the two objects, but this happens only when the orbit is perfectly circular.
Oct
20
awarded  Nice Answer
Oct
19
awarded  Yearling
Oct
19
answered Reason for inertia of motion of Earth orbiting the Sun
Oct
13
comment In electromagnetism, why does nature prefer the right-hand rule over the left-hand rule?
Thanks for including the bit about differential forms; I've been wondering since high school physics why the cross product could only be defined in 3 dimensions and whether there was some other mathematical object that could be used for the same job in higher dimensions.
Jul
31
comment Why do black holes warp spacetime so much more than stars that have the same mass?
@Solomonoff'sSecret Conventionally, the radius of a black hole is the radius of its event horizon (the Schwarzchild radius). That's where the 3km number comes from.
Jul
17
comment Why do I see a saddle in this picture of a computer screen?
@Arthur That's because the red, green, and blue subpixels are not on top of each other, and also there may be some chromatic aberration going on.
May
30
comment If Newton's third law is true, why can we sink in sand?
Also, what Newton's Third Law does mean is that when something starts moving, something else must have started moving in the opposite direction. The trouble is that in the environment familiar to us, very often the something else is the Earth, whose inertia is so immense that its velocity does not appear to change.