Calculating Voltage in an Electromagnet with Known Inductance and Current

AI Thread Summary
An electromagnet operating at 50A with an inductance of 100H will develop a voltage of 5MV when the switch is opened, calculated using the formula V = L(di/dt). The discussion highlights the importance of understanding the relationship between current change and induced voltage, as described by Faraday's law of induction. The switch's operation time of 1 millisecond is noted, but the absence of resistance information initially posed a challenge. Ultimately, the problem was resolved without a circuit diagram. The key takeaway is the significant voltage generated during the rapid change in current.
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Homework Statement


an electromagnet is operated at 50A. assuming an inductance of 100H for the magnet's coil, what voltage will be developed when the switch is opened? when it is closed? assume that the switch requires 1 millisecond to operate.


Homework Equations


I(t) = Vb/(R(1-e^(-tR/L)))


The Attempt at a Solution


with the given formula above I am not quit sure how to proceed if I am not given resistance. any insight on how I should proceed with this problem would be great!
 
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You could use Faraday's law of induction. It gives you the emf developed by a change in the magnetic flux.
 
Is there a circuit diagram to accompany this problem? Maybe that would give us a hint as to the where the resistance is supposed to be, or what might be in place to limit voltages, or what the implications are for a switch that "requires 1 millisecond to operate".
 
no diagram but I figured it out.

di/dt = 50A/10^-7
V = L(di/dt)
V= 5MV
 
thank you everyone!
 

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