Recent content by Marcus95

  1. Marcus95

    Input impedance of a "Ladder" transmission line

    Thank you for your reply! To be honest I have not studied networks in any great detail at all (ie I have no clue what an ABCD matrix is)... this is just an physics EM course which has a 10 page section on transmission lines where this comes up. :/
  2. Marcus95

    Input impedance of a "Ladder" transmission line

    Homework Statement My electronics&physics lecture notes contain the following side note: ___ "A ladder transmission line comprises an alternating sequence of segments of two different transmission lines both of length $l$ with characteristic impedance $Z1$ and $Z2$. If the line is constructed...
  3. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    Are you hinting on that I could calculate alpha for each given value, assuming a linear interpolation for ##H(P_0)##? Or that I should leave it as it is considering the questions says: " Find an expression for α in terms of the enthalpy H(p) of He gas and the enthalpy Hℓ of the liquid. "? and...
  4. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    well yes, that was my initial answer! Does that mean that it cannot be further simplified?
  5. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    Alright, so using the table I can see that by choosing the value at 30 atm, ie the approximate minimum of the H function, I get the maximum alpha. This solves the second part of the question. Now only the first part remains, ie how to express ## \alpha ## in ##H(p)## and ##H_l## only. Any hint...
  6. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    Well the enthalphy is defined as ##H = U + pV ##, or as a differential: ##dH = TdS + V dp## which means that it is indeed a function of p, but what kind of function I don't know. Should I assume a van der Walls gas instead of an ideal one? Would that help?
  7. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    As mentioned in the post, I was assuming ideal gas behaviour but realized it didn't work. This is the reason I am asking for help, to find alternatives. Yes, the equation is a typo. It should indeed read ##1-\alpha##
  8. Marcus95

    Liquidification of Helium under constant Enthelphy Condition

    Homework Statement a)Helium enters a closed system as a flow of compressed gas at a temperature of 14 K and at pressure p (enthalpy conserved). A fraction α emerges as liquid and the rest as gas at 14 K, both at atmospheric pressure p0. Find an expression for α in terms of the enthalpy H(p) of...
  9. Marcus95

    Time Derivative of Rank 2 Tensor Determinant

    Yes, I think it is safe to assume that, even if previous posts are interesting. I have now seemingly solved the problem with help of the exponential form: ## det(A) = e^{lnA} = e^{Tr(lnA)} ## applying differentiation with product rule and assuming it can be taken inside the trace: ##...
  10. Marcus95

    Time Derivative of Rank 2 Tensor Determinant

    Homework Statement Show that for a second order cartesian tensor A, assumed invertible and dependent on t, the following holds: ## \frac{d}{dt} det(A) = det(a) Tr(A^{-1}\frac{dA}{dt}) ## Homework Equations ## det(a) = \frac{1}{6} \epsilon_{ijk} \epsilon_{lmn} A_{il}A_{jm}A_{kn} ## The...
  11. Marcus95

    Finding Total Charge from E-field

    My integral is: ##Q = \int_{r=0}^\infty \int_{\theta=0}^{\pi} \int_{\phi=0}^{2\pi} \alpha\epsilon_0 \frac{e^{-\lambda r}(1-\lambda r)}{r^2} \times r^2sin\theta d\theta dr d\phi ## which gives: ##Q = 4\phi \alpha \epsilon_0 \int_{r=0}^\infty e^{-\lambda r}(1-\lambda r) dr =4\phi \alpha...
  12. Marcus95

    Finding Total Charge from E-field

    Homework Statement A static charge distribution has a radial electric field of magnitude ##E = \alpha \frac{e^{-\lambda r}}{r} ## where λ and α are positive constants. Calculate the total charge of the distribution. Homework Equations Gauss's law ##Q/\epsilon_0 = \int \vec{E} \cdot d\vec{S}##...
  13. Marcus95

    Fringe Visibility of Sodium Doublet in Michelson interferometer

    Thank you @Charles Link , I believe I have gathered a much better insight to Michelson-Morley Inferometers now! :) However, I am afraid I still don't know how to approach the last part of the question I am facing. What is meant by the line-shape and how do I relate the width of it to the fringe...
  14. Marcus95

    Fringe Visibility of Sodium Doublet in Michelson interferometer

    Thank you for your reply @Charles Link , although I am not sure I really follow. The equations you use look like the ones for thin film interference. Is ##\theta## the angle between a light ray and the perpendicular distance to the screen after the beam splitter? But if rays of the two...
  15. Marcus95

    Fringe Visibility of Sodium Doublet in Michelson interferometer

    Homework Statement The sodium D-lines are a pair of narrow, closely spaced, approximately equal intensity spectral lines with a mean wavelength of approximately 589 nm. A Michelson interferometer is set up to study the D-lines from a sodium lamp. High contrast fringes are seen for zero...
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