We can also reason that all the energy in the magnetic field is being dissipated in a short time, so the power dissipated in the spark, P=IV, is large, and this requires a large value of V. (...We can also reason that all the energy in the magnetic field is being dissipated in a short time, so the power dissipated in the spark, P=IV, is large, and this requires a large value of V. (I isn't large --- it is decreasing from its initial value.) Yet a third way to reach the same result is to consider the equation VL=dI/dt : since the time constant is short, the time derivative dI/dt is large.
We can also reason that all the energy in the magnetic field is being dissipated in a short time, so the power dissipated in the spark, P=IV, is large, and this requires a large value of V. (...We can also reason that all the energy in the magnetic field is being dissipated in a short time, so the power dissipated in the spark, P=IV, is large, and this requires a large value of V. (I isn't large --- it is decreasing from its initial value.) Yet a third way to reach the same result is to consider the equation VL=dI/dt : since the time constant is short, the time derivative dI/dt is large.
