What is the current in the wire?

In summary, the conversation discusses the calculation of the current in a 1.2mm x 1.2mm square aluminum wire with an electric field of 2.0×10^-2 V/m. The correct calculation is I = 1.02 A, using the equation I = (1/ρ)*E*A. The value of ρ for aluminum is 2.82×10^−8 ohm-m.
  • #1
Bigworldjust
54
0

Homework Statement



The electric field in a 1.2mm x 1.2mm square aluminum wire is 2.0×10^-2 V/m What is the current in the wire? I = ?A

Homework Equations



E = V/length
R = ρL / A
I = V/R = V*A/ ρ*L

The Attempt at a Solution



Electrical field strength E = V / length = 2 x 10^-2 V/m
Resistance of wire R = ρL / A; ρ for aluminium = 2.65 x 10^-8 ohm-m
A = 1.2*1.2 = 1.44 mm^2 = 1.44 x 10^-6 m^2
Current I = V / R = V*A / ρ*L = (V/L)*(A/ ρ) = 2 x 10^-2 (1.44 x 10^-6 / 2.65 x 10^-8 ) = 1.087 A

Alright that was my final answer, but I am just asking here to double check if it is right or not because I only have one more try on this question, and I don't want to get it wrong, lol. Did I make any mistakes? Thank you!
 
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  • #2
Looks good to me.
 
  • #3
TSny said:
Looks good to me.

Damn, it was wrong, lmao. I still have one more try though luckily. You think there is somewhere I went wrong after rechecking it?
 
  • #4
I check it by another method. Your answer is right. My method is:

I=j*S=(sigma*E)*A=(1/ρ)*E*A=1.80679 A

Where you get the value of ρ? In Wikipedia, it is 2.82×10^−8
 
  • #5
liblenovo said:
I check it by another method. Your answer is right. My method is:

I=j*S=(sigma*E)*A=(1/ρ)*E*A=1.80679 A

Where you get the value of ρ? In Wikipedia, it is 2.82×10^−8

Ah, that was my error. So the answer was 1.02. Thanks for the help!
 
Last edited:

Related to What is the current in the wire?

1. What is current?

Current refers to the flow of electric charge in a circuit. It is measured in amperes (A) and is represented by the symbol "I".

2. How is current measured?

Current is measured using an ammeter, which is connected in series with the circuit. The ammeter measures the amount of charge passing through a specific point in the circuit per unit time.

3. What factors affect the current in a wire?

The current in a wire is affected by the voltage of the power source, the resistance of the wire, and the type of material the wire is made of. It also depends on the length and thickness of the wire.

4. What is the relationship between voltage and current?

According to Ohm's Law, the current in a wire is directly proportional to the voltage and inversely proportional to the resistance. This means that as the voltage increases, the current also increases, and vice versa.

5. Why is it important to measure current?

Measuring current is important in understanding the behavior of electric circuits and ensuring they are functioning properly. It also helps in troubleshooting and making necessary adjustments to maintain the desired level of current in a circuit.

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