Recent content by Quelsita

  1. Q

    Understanding Wave-functions and Normalization?

    Question: 1. An electron is freely moving in a one‐dimensional coordinate, x . At some point t in time, its (complex‐valued) wavefunction is ψ (x,t) = Ceiωte−(x / a)2 . a. Why must \int \left|\Psi|2=1? b. From the so‐called normalization requirement given in part a., determine the...
  2. Q

    Van der Waals gas - free energy

    ok, is the inequality used because the process is not reversible? can L=pdV be applied somewhere? also, I found in our text that deltaF=(dF/dV) dV and it states that this was found using: L< F(A)-F(B)= -deltaF...how is this so?
  3. Q

    Van der Waals gas - free energy

    For this problem, I'm really jst trying to figure out everything that is going on and then I can simply follow through with the derivatives once I know what I'm working with. Q: For the van der Waals gas, introduce the free energy as F = U – TS and verify that its derivatives over V and T...
  4. Q

    Adding, subtracting, and converting phasors to polar form

    Ok, I'm trying to wrap my head around phasor notation. I think part a is correct, not sure of the difference for subtraction and converting phasor to polar notation. Any help is appreciated! Problem: For A=5<36.9 and B=5<53.1 a)Calculate the sum A+B b)Calculate the difference A-B...
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    Heat needed to double gas volume at constant pressure

    Honestly, I'm kinda stuck here. It feels to me like with the information I have that I'm just going in circles using one equation to solve another one. I don't think this question should even be this confusing...
  6. Q

    Heat needed to double gas volume at constant pressure

    Well, for an ideal gas PV=nRT. And since P is constant, can I say that: P0 = (nRT0)/V0 is the same as P= (nRT0)/V0 so , P= [(273.15K)(nR)]/V0
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    Heat needed to double gas volume at constant pressure

    Question: One mole of an ideal gas with cv=2.5R, initially at 0.0degC, is heated at constant pressure. How much heat is needed to double its volume? Solution: Know: n=1 T0=273.15K cv=2.5R \DeltaP=0 Vf=2V0 H=U +PV and thus, Q= \DeltaH Q=ncv\DeltaT We can rearrange to find...
  8. Q

    Calculate the electrostatic energy of a homogeneously charged sphere

    QUESTION: Calculate the electrostatic energy of a homogeneously charged sphere of Volume V and compare the result with 2 times the electrostatic energy of a homogeneously charged sphere of V/2. SOLUTION: OK, so we have a charge Q which is uniformly distributed within a sphere of...
  9. Q

    Electron Energy in Compton Collision

    Question: You want to give an electron an evergy of 25kev in a Compton Collision. What is the minimum initial photon energy you need? Equations: \Delta\lambda= h/mec(1-cos(\theta)) E=mc2 E=hv=hc/\lambda I'm not really sure where to start from here. I know the answer is 138kev but I am...
  10. Q

    Graduate Waves, Energy, Blackbodies and Modes

    That makes sense but "eigenstate" threw me off a bit. So, if an eigenvalue is a scalar, then that just means an eigenstate for, say a photon, would be every possible path it can take? This is why a mode is a degree of freedom, because it describes the possible configurations? So, if you...
  11. Q

    High School Do heavier objects hit the ground first in air resistance?

    Wouldn't they reach the ground at equal rates? Generally, free fall implies that no other acclerations are acting other than gravity (objects don't encounter a significant amount of air resistace). If we considered drag, it would depend on the shape (surface area) of the object, and since...
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    Graduate Waves, Energy, Blackbodies and Modes

    I am going over some notes and am trying to fit some pieces together. For some reason I keep confusing myself as to what exactly a "mode" is. Is a mode a wave? or a frequency? Also, how does a mode relate to the degrees of freedom for a particle in a system? Thanks!
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    Percent Length Contraction (check solution)

    Yep. That's why I thought it was off because it's such a small number that you'll have 1 under the radical... Or is the percent contraction supposed to be very small since the aircraft, compared to the speed of light, is going extremely slow?
  14. Q

    Percent Length Contraction (check solution)

    Question: What is the percent length contraction of an aircraft traveling at Mach 2? So, we know that Mach 2= 680.58 m/s and that L'=L\sqrt{1-(v/c)^2} If you divide over the L to get: L'/L=\sqrt{1-(v/c)^2}=% length contraction Plug-n-chug from here to get...
  15. Q

    Calculating Time Dilation: Apollo's Record-Breaking Speed and Earth's Clocks

    Yeah, I actually converted the velocity to m/s I just skipped the conversion work.