Know the total resistance of the whole circuit

In summary, the conversation discusses the behavior of bulbs in a DC circuit and compares it to the flow of a river. The participants question why the first bulb in the circuit does not receive more energy than the second one, similar to how a boulder in a river slows down the flow downstream. However, the expert explains that a circuit can only have one amperage and the change in the circuit will take some time to adjust, just like how adding a rock to a river will cause a delay in the flow. They also explore the concept of erosion and how it relates to the brightness of a bulb. Ultimately, the expert concludes that the analogy to a river is not a perfect one, but serves to illustrate the concept of energy distribution in
  • #1
239
0
please feel free to move this thread as i cannot find the correct place.


in a series (dc), when two bulb of the same resistance is used, the two bulbs lighted up as bright. when one bulb is used instead of two, the bulb ligth up brighter.

if again, two bulb arrange in circuit, why not the bulb nearrer to the negative end light up brighter then the next one. it seems that the electron already know the total resistance of the whole circuit at the first bulb to decide the amount of energy relesed at the bulb.

am i messing up some where?
 
Physics news on Phys.org
  • #2
A circuit can only have one amperage just as a river can only have one flowrate. Tossing a massive rock into a river doesn't make the rest of the river instantly "know" the flowrate has changed, there is a short delay as the flow through the entire river adjusts to the change, starting at the point where the change was made. Same goes for electricity: if you suddenly attached a second light, the circuit would not react instantly to the change.
 
  • #3
It would react pretty quick though!
 
  • #4
by using water, for example the brightness of the lamp is equal to the erosion of rock.

in the first place, when there is a boulder at the high land, it slows down current after the river or decreasing it's volume. and so when there is another boulder at the low land, it won't be eroded as much as the high land as it already lost it's energy.

a bad example actuallly, but i couldn't find a better one.
 
  • #5
If the river flows at the same rate all the way along (as current does in a circuit) the rock erosion would be identical everywhere!
 
  • #6
no, i meant that it flow slower down stream as the energy had been used upstream
 

1. What is resistance in a circuit?

Resistance is a measure of how much a material or component opposes the flow of electric current. It is typically measured in ohms (Ω) and is represented by the symbol 'R' in equations.

2. How is the total resistance of a circuit calculated?

The total resistance of a circuit is calculated by adding up the individual resistances of all the components in the circuit. This can be done using Ohm's Law, which states that resistance is equal to the voltage divided by the current (R=V/I).

3. What factors affect the total resistance of a circuit?

The total resistance of a circuit is affected by the type of material used for the components, the length and thickness of the wires, and the temperature of the circuit. In general, longer and thinner wires have higher resistance, while thicker wires and cooler temperatures have lower resistance.

4. Why is it important to know the total resistance of a circuit?

Knowing the total resistance of a circuit is important because it allows us to calculate the amount of current that will flow through the circuit for a given voltage. This is crucial for designing and troubleshooting electronic systems, as well as ensuring that the components in the circuit are not overloaded.

5. How does the total resistance impact the functioning of a circuit?

The total resistance of a circuit impacts the functioning of the circuit by affecting the amount of current that can flow through it. A higher resistance will result in a lower current, while a lower resistance will allow for a higher current. This can impact the performance and efficiency of the circuit, as well as the lifespan of the components within it.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
130
Replies
35
Views
10K
  • Introductory Physics Homework Help
Replies
6
Views
629
  • Electromagnetism
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
746
  • Electromagnetism
Replies
4
Views
1K
  • Other Physics Topics
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
2K
Back
Top