Three light bulbs in parallel circuit and Currents

In summary, in a parallel circuit with three light bulbs, removing one light bulb will decrease the current of the entire circuit. This is because the overall resistance of the circuit decreases and voltage remains the same, resulting in a decrease in current according to the formula I = V/R. This may seem counterintuitive, but it is due to the fact that resistors in parallel have an inverse relationship in terms of resistance. It is important to study parallel circuits to fully understand this concept.
  • #1
kfreshn
5
0

Homework Statement



Pretend you have three light bulbs in a parallel circuit and one light bulb goes out/removed so that there two light bulbs remaining.

Does current of the entire circuit increase, remain same, or decrease after the one of the bulb is removed.

The answer is decrease.

I thought it would have increased.
i'm slightly confused here, doesn't the current in the overall circuit increase since the resistance of the circuit has decreased if you remove one light bulb.

Afterall, I (of circuit) = V/R. When one light bulb(resistor) is removed from a parallel circuit, the overall Resistance of the circuit decreases and the Voltage remains the same,thus shouldn't the current of the circuit increase?

Lets say each light bulb resistance is 2 ohms. And battery is 3V.

At first with all 3 connected: for resistors connected in parallel its 1/2+1/2+1/2 = 1.5
Thus, I=V/R --> 3/1.5 = 2 Amps.
When one light bulb is removed, the overall resistance is 1/2 + 1/2 = 1.0
Thus, I=V/R --> 3/1.0 = 3 Amps.

Thats how i logically and mathematically reason the answer should have been the overall current in the parallel circuit increases when one of the three light bulb burns out or is removed.

All help is appreciated.
 
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  • #2
kfreshn said:
i'm slightly confused here, doesn't the current in the overall circuit increase since the resistance of the circuit has decreased if you remove one light bulb.

Well, if the resistance decreased, then the currently certainly WOULD go up, but since the resistance increases, the current goes down.

You need to study parallel circuits.
 
  • #3
phinds said:
Well, if the resistance decreased, then the currently certainly WOULD go up, but since the resistance increases, the current goes down.

You need to study parallel circuits.

Oh thank you very much. I rechecked and it was 1/R=(1/R1)+(1/R2)+... etc

I miswrote my formula was R=(1/R1)+(1/R2)+...etc

Thank you very much for your time and help!
 

FAQ: Three light bulbs in parallel circuit and Currents

What is a parallel circuit?

A parallel circuit is a type of electrical circuit where the components are connected in a way that allows multiple paths for the current to flow. This means that if one component fails, the current can still flow through the other paths in the circuit.

How do three light bulbs in a parallel circuit affect the current?

In a parallel circuit, the current is divided into different branches, with each branch receiving the same voltage. This means that the three light bulbs will each have the same voltage across them, resulting in equal brightness. However, the total current in the circuit will be the sum of the individual currents in each branch.

What is the advantage of using a parallel circuit for three light bulbs?

One advantage of using a parallel circuit for three light bulbs is that the bulbs will have the same brightness, regardless of the number of bulbs in the circuit. This is because the voltage across each bulb remains the same, even as more bulbs are added. Additionally, if one bulb burns out, the other two will still function, providing a continuous flow of light.

How does the current change if one light bulb is removed from a parallel circuit?

If one light bulb is removed from a parallel circuit, the total current in the circuit will decrease. This is because, in a parallel circuit, the current is divided between the different branches. With one less bulb, there is less resistance in the circuit, resulting in a decrease in the total current.

What is the difference between series and parallel circuits?

In a series circuit, the components are connected in a single path, meaning that the current has to flow through each component in order. In a parallel circuit, the components are connected in different branches, allowing the current to flow through each component separately. Additionally, in a series circuit, the voltage is divided among the components, while in a parallel circuit, the voltage is the same across each component.

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