Recent content by laser

I'm just reading some notes, it says that equation (1) is a postulate, but it also said that the sum of |A_p|^2 = 1 is also a postulate. Probably just a mistake in the notes, as either postulate can be used to derive the other! Source...

Ah okay I see. You get the sum over m of |A_m|^2 which is equal to the above image. As it turns out, the above image is also equal to the probability density over all the space = 1! (from another postulate) This leads to another question: why is |A_p|^2 = probability density a postulate as...

Firstly, I am not sure why you changed the subscripts when going to the wavefunction conjugate. Also, the equation you asked me to consider is the same one in my image! So I will get A_m. But I don't see how that answers my question.

The first equation states that every wavefunction can be written as a sum of wavefunctions of definite momentum, with A_p being defined as the coefficients in the expansion such that when you take the |wavefunction|^2 it equals 1 - fine. We then multiply by the wavefunction conjugate and...

volume is 10 m^3

I think it is correct

Source: Shankar Yale OCW physics I have three questions here: 1. K_avg is 3/2kT, sure. But isn't this the kinetic energy of one particle only? So why isn't the answer multiplied by avogadro's number (because one mole). 2. When doing the "typical velocity" derivation, I noticed that they used...

Is this what you mean?

I'm not sure what you are asking me.

I am a bit confused on the marking scheme as attached above. P1V1 is a constant by Boyle's Law. If the volume increases by a factor of 3, then the pressure decreases by a factor of 3. This means that the pressure at the top is 1/3 the pressure at the bottom, right? The pressure at the top is...

Yes

I am uncertain if this represents situation (a) or situation (b). i.e. is 2 = E-iR or is 2 = E? Or is the question ambiguous? Thanks!

Thanks guys, for some silly reason I got mixed up with di/dt and i! The general pattern of the decrease in the induced emf makes sense now, and the fact that the decrease is exponential is from the DE.

I might have misphrased my original question... "So what happens then? IDK! My guess is that the two emfs cancel out, (which seems reasonable), and that means current is 0. Okay, fine, the book agrees with me. But what happens next? I know what is supposed to happen - the induced emf goes from...

Yes, the maths behind deriving this makes sense to me. But not the conceptual understanding. Because if di/dt = 0, then surely induced emf = 0 too! But no, the induced emf exponentially shrinks to 0...