Recent content by Raihan amin

  1. Raihan amin

    Understanding a heat sensor circuit?

    What I understand is that the β parameter of the npn transistor is temperature dependent. Increasing the temperature increases the collector current and hence the LED turns ON. But I don't understand the resistor arrangement.Also I can see that the diode is keeping the Base-Emitter junction in...
  2. Raihan amin

    I A claim regarding Fourier Series

    This is written on Greiner's Classical Mechanics when solving a Tautochrone problem. Firstly,I don’t understand why we didn’t use the term ##m=0## and Sencondly, how the integrand helps us to fulfill the Dirichlet conditions. That means,how do we know that the period is 1?Thanks
  3. Raihan amin

    The potential between a cone and a plate

    Now using this formula,you can find E too.
  4. Raihan amin

    The potential between a cone and a plate

    Now put these value in the Original equation,and you are done.
  5. Raihan amin

    The potential between a cone and a plate

    You can do this by using the boundary condition on ##V##,i.e, $$V(\frac{\pi}{2}) =0$$
  6. Raihan amin

    The potential between a cone and a plate

    What you have calculated is the potential difference between two coaxial cone ,where the inner one has a potential of ##V## at ##{\theta}_1## and the outer one has a potential of 0 at ##{\theta}_2##. So check your calculation again,and find the right equation which fulfill the boundary...
  7. Raihan amin

    Finding recoil velocity of an object during a collision

    I wonder how a photon could have a mass.
  8. Raihan amin

    Finding recoil velocity of an object during a collision

    ##\frac v c =\frac 1 5## ,not so negligible,so you have to perform relativistic calculations
  9. Raihan amin

    Relationship between Excess Pressure and Surface Tension for a Drop on a Fibre

    Homework Statement Think of a drop of radius ##R## deposited on a fibre of radius ##b(b<<L)##.Find ##{\Delta{P}}## Homework Equations The relationship between excess pressure and the surface tension is given by Yong-Laplace equation, $$\Delta{P} = \sigma{(\frac{1}{R_1}+\frac{1}{R_2})}$$ The...
  10. Raihan amin

    Superconductor in an external magnetic field

    I know that way,but it is also a valid process i think. You can see page 305 of "A Guide to Physics Problems" by Cahn and Nadgorny
  11. Raihan amin

    Superconductor in an external magnetic field

    Homework Statement A superconducting spherical shell of radius R is placed in a uniform magnetic field ##\vec{B_0}## 1)Find the magnetic field everywhere outside the shell 2)the sutface current density Homework Equations Inside the shell the net magnetic field is 0, and at the surface also...
  12. Raihan amin

    Shape of a bubble inside a rotating container

    And i have no idea about the shape of the bubble when the cylinder starts rotating. Please give the actual answers of your questions .
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