Recent content by omegas

  1. O

    Tricky Derivation of Blackbody Equations.

    Homework Statement Starting with the Planck distribution: R(\lambda,T) = \frac{c}{4} \frac{8 \pi}{\lambda^4} (\frac{hc}{\lambda})(\frac{1}{e^{hc/(\lambda kT)}-1}) Derive the blackbody Stefan-Boltzmann law (ie total flux is proportional to T4) by integrating the...
  2. O

    Calculating Black Hole Mass Limit for Gravitational Acceleration Change

    Thanks. I did the calculations, but I keep getting a negative number. I set my r = 50Rs and for my dg/dr I get -2GMr-3. So when I solve for M is keep getting a negative number.
  3. O

    Orbits of Particle Around a Black Hole using Effective Potential

    Homework Statement The possible orbit of a particle moving around a black hole can be described using the effective potential UGR(r) (in effect, potential energy per unit mass): UGR(r) = -GM/r + l2/2m2r2 - Rsl2/2m2r3 where the symbols have their usual meaning and in particular...
  4. O

    Derive Stefan-Boltzmann Law from Planck Distribution for blackbody radiation

    Homework Statement Starting with the Planck distribution R(\lambda,T) for blackbody radiation. (a) Derive the blackbody Stefan-Boltzmann law (ie total flux is proportional to T4) by integrating the above expression over all wavelengths. Thus show that R(T) =...
    • omegas
    • Thread
    • Blackbody Blackbody radiation Derive Distribution Law Planck Radiation Stefan-boltzmann Stefan-boltzmann law
    • Replies: 2
    • Forum: Advanced Physics Homework Help
  5. O

    Calculating Black Hole Mass Limit for Gravitational Acceleration Change

    Homework Statement Calculate the black hole mass limit such that the change in the gravitational acceleration at a distance 50Rs over a small interval of 2m doesn't exceed 10m/s2. Use Newton's Theory of Gravity in the calculation. Homework Equations Schwarszchild Radius: Rs = 2GM / c2...
  6. O

    Minimum Uncertainty in Measuring Velocity of a Particle in X-direction.

    Hmmm...could I just set \Deltap = h \Deltax? The change in x would be the difference in the edge of the disc and the side of the tray in the x direction, right? So \Deltax would be 4mm to the side of the tray. I know h = 6.62*10-24 and p = m v and my mass would be 5mg. So if I fenagle around...
  7. O

    Minimum Uncertainty in Measuring Velocity of a Particle in X-direction.

    What I really don't understand is that it says the disk is at rest, which I am assuming means there is no velocity, so how can I measure \Deltap?
  8. O

    Minimum Uncertainty in Measuring Velocity of a Particle in X-direction.

    Homework Statement A small flat circular disc of diameter 2mm and mass 5mg is lowered vertically to rest at the centre of a flat tray of width 10mm in the x direction and 50mm in the y direction. What is the minimum uncertainty in measuring the velocity of the particle in the x direction...
  9. O

    Energy to Increase Orbital Radius

    Homework Statement An Earth (mass M) satellite of mass m is in a circular orbit of radius r1. It is moved to an orbit with a larger radius r2 by way of an intermediate elliptical orbit. This is achieved by firing rockets for a short period when it is in the inner orbit, and then firing the...