Does a current instantaneously disappear?

[perplexabot]

Hi all. I was working on a circuit question with inductors and I then had a question. Let's say we have a simple circuit with only a resistor, an emf source and a switch. We first close the switch and the current goes though. Now after some time we open the switch.

My question is: Just after we open the switch does the current instantly go to zero? Or will the resistor have a current running through it at that instant and then decay?

Thank you

 

[Drakkith]

I believe the EMF takes a finite time to propagate, so when you open the switch not only is there a small amount of time that it takes for the switch to completely cut the voltage and current, the rest of the circuit should take a small amount of time to dissipate the remaining current.

 

[phyzguy]

If the inductance in the circuit were truly zero, the current would vanish instantly. However, all real circuits have some inductance, so the current will decay with a time constant given by L/R.

 

[perplexabot]

Alright, so assuming the circuit has zero inductance (which is what I think my physics book is doing) then the current will immediately stop after the switch is opened. Thanks.

 

[sardar]

for your question. The current in a circuit does not instantaneously disappear when a switch is opened. When the switch is closed, the current flows through the circuit due to the flow of electrons. However, when the switch is opened, the flow of electrons is suddenly interrupted, but the current does not immediately drop to zero. This is because of the inductance in the circuit, which resists any change in current. As a result, the current will continue to flow for a brief moment before eventually decaying to zero. This process is known as inductive kickback. The amount of time it takes for the current to reach zero depends on the inductance of the circuit and the resistance of the components. Therefore, the current does not disappear instantaneously but rather decays over a short period of time. I hope this helps clarify your question.