Recent content by anizet

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    Phase problem in a damped RLC circuit

    OK, so my result was correct. But could somebody explain to me the physical meaning of it? It is not intuitive...
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    Phase problem in a damped RLC circuit

    Homework Statement The expression for electric charge on the capacitor in the series RLC circuit is as follows: q(t)=A*exp(-Rt/2L)*cos(omega*t+phi) where omega=square_root(1/LC-R^2/4L^2) What is the phase phi, if the initial conditions are: q(t=0)=Q I(t=0)=0 Homework Equations The damped...
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    Calculating Decay Rates of a Nucleus with 2 Channels

    Well. I'm not sure yet. Thank You any way.
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    Calculating Decay Rates of a Nucleus with 2 Channels

    yes, that's what I mean.
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    Calculating Decay Rates of a Nucleus with 2 Channels

    I mean that after 20 hours N=N0/e.
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    Calculating Decay Rates of a Nucleus with 2 Channels

    Homework Statement A nucleus decays into two channels with probabilities 0.62 and 0.38, respectively. Its lifeime is 20 hours. What are the decay rates into each of these channels? Homework Equations If there is only one channel of decay, the decay can be described by the formula...
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    Undergrad Efficiency of heat pump and refrigerator

    I know the formulas for efficiencies e of heat pump (it is e<=Tmax/(Tmax-Tmin)) and refrigerator (e<=Tmin/(Tmax-Tmin)), where Tmax and Tmin are temperatures of warmer and colder (respectively) involved containers. These formulas make me puzzled, as efficiencies seem to be possibly bigger than 1...
    • anizet
    • Thread
    • Efficiency Heat Heat pump Pump Refrigerator
    • Replies: 2
    • Forum: Thermodynamics
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    Analyzing 2-Lens System: Image Position, Magnification & Nature

    Homework Statement A convex lens (f1=300mm) is placed 200 mm from a concave lens (f2=-50mm). An object is placed 6m away form the convex lens. (the order is as follows: object - 6m - convex lens - 200mm - concave lens). Determine the position, magnification and nature of a final image...
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    Potential inside of chrged non-conductive sphere

    One more correction: Why should I integrate from infinity to r not from zero to r? I hope, now it's ok...
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    Potential inside of chrged non-conductive sphere

    Sorry again: from inf to r not from r to inf, I meant.
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    Potential inside of chrged non-conductive sphere

    Thank you very much for the reply! I have just one more question: why should I integrate from infinity to zero, not from zero to infinity?
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    Potential inside of chrged non-conductive sphere

    I made a small mistake in typing the formula on V that I obtained. It should be: V(r)=-q*r^2/(8*PI*e0*R^3)
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    Potential inside of chrged non-conductive sphere

    Homework Statement A charge is distributed uniformly throughout a non-conducting spherical volume of radius R. Show, that the potential at distance r from center (r<R) is given by: V=q(3*R^2-r^2)/(8*PI*e0*R^3) Homework Equations From Gauss low: E(r)=q*r/(4*PI*e0*R^3) E(r)=-grad(V(r))...