What Is the Diameter of a Nichrome Wire in a Circuit?

[dismalice]

Homework Statement

A 19-cm-long nichrome wire is connected across the terminals of a 1.8 V battery. If the current in the wire is 2.1 A, what is the wire's diameter in mm?

Homework Equations

R = Rho*L
--------
A
v=ir

The Attempt at a Solution

rho for this = 100 e -8.

V=IR
TF,
R = .86 Ohms
100 e -8(.19)
-------------
.86

= 2.21 e -7 m^2

A = pi * r^2

(2.21 e -7/pi)^.5 = r

= 0.000265229118 m.

= 0.265229118 millimeters

 

[vela]

Note the question is asking for the wire's diameter, not its radius.