Ratchit,
To answer your question: Yes Vf can be more than a few volts. If you look at the IV curves you will notice the voltage goes up slowly with current. So if you look at a curve (like below) you can see that in this diodes case it is about 6.25 volts per amp. From this we can draw a few conclusions:
Your 3500 amp number ain't gonna happen.
The number will be more in the order of 50 to 60 amps. Not that that is to important except it explains why the time constant is longer. It's still about 60 mj.
While the energy is still the same with the resistor in series, with the resistor most of the energy is in the resistor and not the diode.
PS. If you look at a few good LED datasheets you will find some with specs on maximum current vs time. IR seem to be the best, White the worst. Guess that makes sense.
To answer your question: Yes Vf can be more than a few volts. If you look at the IV curves you will notice the voltage goes up slowly with current. So if you look at a curve (like below) you can see that in this diodes case it is about 6.25 volts per amp. From this we can draw a few conclusions:
Your 3500 amp number ain't gonna happen.
The number will be more in the order of 50 to 60 amps. Not that that is to important except it explains why the time constant is longer. It's still about 60 mj.
While the energy is still the same with the resistor in series, with the resistor most of the energy is in the resistor and not the diode.
PS. If you look at a few good LED datasheets you will find some with specs on maximum current vs time. IR seem to be the best, White the worst. Guess that makes sense.