00:01
In this question, we have a parallel plate capacitor with circular plates with a uniform electric field between the plates and at t equals zero the difference between the two plates is given by b is equal to 100 volts exponential of manis t over tau where the time constant is 12 milliseconds and we want to know what is the magnetic field, magnitude, as a function of time, and at the time equals 3 -tall.
00:46
So the magnetic field will be proportional to the variation of the electric field.
00:51
So we have the magnetic field for this case is mu -0, epsilon 0 over 2, the d -d -t, for r smaller than capital r.
01:05
And we have that d d d d dt is equal to 1 over d, d, vdt.
01:15
And v is this function here, so it is minus v0 over t tau d, exponential of minus t over t.
01:30
And then the magnetic field we can find directly, magnetic field, is minus mu zero, epsilon zero, v zero, r divided by 2 t t xo d, exponential of minus t over t.
01:48
And this is the expression for the magnetic field...