Really basic what happens when the switch closed question

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Homework Help Overview

The discussion revolves around a circuit problem involving three identical lamps connected to a battery with a switch. The original poster questions why lamp C turns off when the switch is closed, despite the expectation that current would divide among the lamps.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to understand the behavior of current in the circuit, specifically why lamp C does not receive current when the switch is closed. Some participants discuss the concept of resistance in relation to the current flow.

Discussion Status

Participants are exploring the reasoning behind the current flow in the circuit. Some have provided insights into the relationship between resistance and current paths, suggesting that the switch's low resistance affects the current distribution. There is an acknowledgment of the original poster's growing understanding of the concept.

Contextual Notes

There is an assumption that the resistance in the switch and wires is negligible for theoretical problems, which is a point of discussion among participants.

sameeralord
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Hello guys,

I got a small question. It says circuit consists of three identical lamps connected to a battery with a switch as shown in the diagram. When the switch is closed what happens.

I did this really quick on paint.

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they are not allowing me to post URL because I don't have 15 posts. I'll do some spaces and stuff please type the w w w thing properly.

It says that lamps C turns off because no current flows through it. But I don't get it. Shouldn't the current divide and each section get some current. Why is C getting no current when the switch is closed. Any help would be appreciated. Thanks:rolleyes:smile:
 
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You are supposed to have both positive and negative current for the lamp to turn on, no?
 
sameeralord said:
Hello guys,
...
It says that lamps C turns off because no current flows through it. But I don't get it. Shouldn't the current divide and each section get some current. Why is C getting no current when the switch is closed. Any help would be appreciated. Thanks:rolleyes:smile:

The switch and wire in parallel with the "C" lamp have extremely low resistance.
The "C" lamp will have much higher resistance in comparison.
When the switch is closed, nearly all of the current will flow through the switch.
The current flowing through the lamp will not be sufficient to cause it to illuminate.

For theoretical schoolwork problems, the resistance in the switch and wires are generally assumed to be zero. So when the switch is closed, there will be no voltage drop across the "switch" leg of the circuit. With no voltage drop across the "C" lamp, there will be no current.
 
OmCheeto said:
The switch and wire in parallel with the "C" lamp have extremely low resistance.
The "C" lamp will have much higher resistance in comparison.
When the switch is closed, nearly all of the current will flow through the switch.
The current flowing through the lamp will not be sufficient to cause it to illuminate.

For theoretical schoolwork problems, the resistance in the switch and wires are generally assumed to be zero. So when the switch is closed, there will be no voltage drop across the "switch" leg of the circuit. With no voltage drop across the "C" lamp, there will be no current.

Thank you for your help:smile:. I think I get it now. The current took the path of least resistance in this circuit. Let's say there was a resistor in the wire with the switch then you would see more current flow to the globe. Am I right!. Thanks a lot for the help. Really appreciate it. :smile:
 
sameeralord said:
Thank you for your help:smile:. I think I get it now. The current took the path of least resistance in this circuit. Let's say there was a resistor in the wire with the switch then you would see more current flow to the globe. Am I right!. Thanks a lot for the help. Really appreciate it. :smile:

Exactly right.
 

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