Electric field in a wire with same current as another wire

If so, you might want to ask your instructor if the values are correct. Good luck!In summary, in order for the current in a 2.0-mm-diameter nichrome wire to be the same as the current in a 1.0-mm-diameter gold wire with an electric field strength of 0.0095 N/C, the electric field strength in the nichrome wire would need to be 0.0973 N/C. However, if the resistivity values used are incorrect, the answer may be different. It is recommended to double check the values with your instructor.
  • #1
ricky25j
1
0

Homework Statement


For what electric field strength would the current in a 2.0-mm-diameter nichrome wire be the same as the current in a 1.0-mm-diameter gold wire in which the electric field strength is 0.0095 N/C?

dn = .002m
dg = .001m
Eg = .0095 N/C

ρn = 100 * 10-8 Ωm
ρg = 2.44 * 10-8 Ωm

Homework Equations


V = IR
R = ρL/A
V = E * Δs

The Attempt at a Solution


[/B]
First, I found a general equation for current in a wire:

V = IR
I = V/R
I = (E*Δs)/(ρL/A)
I = EA/ρ

Then, I used this to find the current in the gold wire (and by extension, the nichrome wire).

In = Ig = Eg * Ag / ρg

I then used the I = EA/ρ equation to find an expression for the electric field in the nichrome wire, and plugged in the above value for the current.

En = In * ρn / An
En = (Eg * Ag * ρn) / (ρg * An)

I then plugged in the values and solved.

En = [(.0095 N/C)(π*(.001m)2/4)(100*10-8Ωm) / [(2.44*10-8Ωm)(π*(.002m)2/4)]

= .0973 N/C

Webassign is not accepting this answer. Does anyone know where I went wrong?
 
Last edited:
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  • #2
Welcome to PF!

Your work looks correct. Did you get the values of the resistivities from you textbook?
 

1. What is an electric field?

An electric field is a physical phenomenon that exists around an electrically charged object. It is a force field that exerts a force on other charged objects within its vicinity.

2. How is an electric field created in a wire?

An electric field is created in a wire when an electric current flows through it. The flow of charged particles, such as electrons, creates a force field around the wire.

3. What is the significance of having the same current in two wires?

Having the same current in two wires means that they have an equal amount of charged particles flowing through them. This can be used to compare the strength of the electric field surrounding each wire.

4. How does the electric field in a wire with the same current as another wire differ from the other wire?

The electric field in a wire with the same current as another wire will have the same strength and direction as the other wire's electric field. However, the shape and distribution of the electric field may differ depending on the placement and orientation of the wires.

5. Can the electric field in a wire with the same current as another wire be manipulated?

Yes, the electric field in a wire with the same current as another wire can be manipulated by changing the current, altering the placement or orientation of the wire, or by introducing other electrically charged objects into its vicinity.

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