Recent content by Joseph Rolls

  1. J

    Magnetoresistance and the Corbino disk

    My answers so far are: a) J=I/(2*pi*r*t) b) u=J/ne=I/(2*pi*r*t*n*e) c) F=IB/(2*pi*r*t*n), in theta direction (polar coordinates) d) This is where I am stuck. I understand the example for motional emf with a rod moving through a magnetic field but I'm not sure how to apply it to this scenario...
  2. J

    Finding heat capacity for liquids

    liquid melting point (degrees C) boiling point (degrees C) water (H2O) 0 100 sodium (Na) 98 883 Sodium-potassium(NaK) -11 785 Lead(Pb) 327 1749 I'm prettttty sure by consulting the literature means by using the above table… but if that's the case then how in the world do you find Cv...
  3. J

    Electric and Magnetic field acting on an electron

    oh yeahhh of course, that was stupid of me, I found the particular solution ## v_{xp}=\frac{V}{bd} ##, but forgot to include it. Awesome, I get the same solutions for vx, vy and s as you and delta^2 too now. That being vx=-V/(Bd)cos(Bqt/m)+V/Bd and the other two as stated. Thanks heaps again...
  4. J

    Electric and Magnetic field acting on an electron

    ok so i got ## v_x ## = Acos(qbt/m)+Csin(qbt/m) for the homogeneous solution, but if ## v_x ## = 0, when t=0, then doesn't that imply A=0 so we eliminate the Acos(qbt/m) from our equation instead of the sin? although i think this is wrong because this leads me to get ## v_x ## = V/Bd and that...
  5. J

    Electric and Magnetic field acting on an electron

    Sorry, this is probably a really stupid question, but how is it a second order equation?
  6. J

    Electric and Magnetic field acting on an electron

    oh yep, i forgot that minus sign, i wondered why i had an extra one later one. what you've said in your second post is what i said before but maybe i didn't make it clear. kinetic energy increase is the decrease in potential energy from the electric field which is qV, and so we have...
  7. J

    Electric and Magnetic field acting on an electron

    Ok…so i subbed in ##\vec{v}=v_x\vec{i}+v_y\vec{j}## and got $$m_e\frac{d\v_x\vec{i}}{dt}=q\frac{V}{d}\vec{j}+q\vec{v}\times \vec{B} $$ and $$m_e\frac{d\v_y\vec{j}}{dt}=q\vec{j}(frac{V}{d}+\vec{v_y}\times \vec{B}) $$ and said that for the electron to just not touch the top plate, the force in the...
  8. J

    Electric and Magnetic field acting on an electron

    Well initially it is to the right, but as the electron changes direction the magnetic force direction will also change, swinging around until it points down as the electron just nearly touches the plate, it means the radius will be curved but it won't be a circular trajectory because of the...
  9. J

    Electric and Magnetic field acting on an electron

    Homework Statement In the figure, an electron of mass m, charge − e, and low (negligible) speed enters the region between two plates of potential difference V and plate separation d, initially headed directly toward the top plate. A uniform magnetic field of magnitude B is normal to the plane...
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