Ammeter from parallel to series, current change

In summary, a student mistakenly connects a perfect ammeter in parallel with one of two identical resistors and the ammeter reads 0.40A. However, the correct reading would have been 0.20A if the ammeter had been connected in series with the two resistors. This is because the ammeter has a negligible resistance and in parallel, it would have a lower effective resistance, resulting in a higher current reading. This mistake can be understood by reading about the relationship between resistance and current.
  • #1
Faris A
5
0

Homework Statement


In the circuit shown, a student mistakenly connects a perfect ammeter(i.e. One of negligible resistance), in parallel with one of two identical resistors. The ammeter reads 0.40A.

What would the reading have been if he had correctly connected the ammeter in series with the two resistors? The cell also has negligible resistance.

Homework Equations


Relevant circuit (http://imgur.com/Uo6w6Um)

The Attempt at a Solution


I have no idea, the textbook says the answer is 0.20A but I have no idea why.
 
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  • #2
Faris A said:
I have no idea,
Faris A said:
two identical resistors
Think about it.
 
  • #3

1. What is the difference between connecting an ammeter in parallel and in series?

Connecting an ammeter in parallel means that the ammeter is connected in a separate branch of the circuit, allowing the current to flow through the ammeter and the rest of the circuit simultaneously. On the other hand, connecting an ammeter in series means that the ammeter is connected directly in line with the circuit, forcing all of the current to flow through the ammeter first before reaching the rest of the circuit.

2. How does connecting an ammeter in parallel affect the current in the circuit?

Connecting an ammeter in parallel has little effect on the current in the circuit. This is because the ammeter has a very low resistance, so it does not significantly alter the overall resistance of the circuit. Therefore, the current in the circuit will remain relatively unchanged.

3. Why would you want to connect an ammeter in parallel instead of in series?

Connecting an ammeter in parallel allows you to measure the current in a specific branch of the circuit without disrupting the overall current flow. This can be useful when trying to isolate and measure the current in a particular component or section of the circuit.

4. How does connecting an ammeter in series affect the overall resistance of the circuit?

Connecting an ammeter in series adds its own resistance to the circuit, which can affect the overall resistance. This is why it is important to use an ammeter with a very low resistance, so that it has minimal impact on the overall resistance of the circuit.

5. What are the potential dangers of using an ammeter in a circuit?

Using an ammeter in a circuit can be dangerous if it is not done properly. If the ammeter is connected in parallel, it could cause a short circuit, which can damage the ammeter and other components in the circuit. Additionally, if the ammeter is not rated for the amount of current in the circuit, it could overheat and potentially cause a fire. It is important to always use caution and follow proper safety procedures when using an ammeter in a circuit.

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