   Chapter 17, Problem 31P

Chapter
Section
Textbook Problem

(a) A 34.5 -m length of copper wire at 20.0°C has a radius of 0.25 mm. If a potential difference of 0.0 V is applied across the length of the wire, determine the current in the wire. (b) If the wire is heated to 30.0°C while the 9.0-V potential difference is maintained, what is the resulting current in the wire?

(a)

To determine
The current passing through the copper wire.

Explanation

Given Info: The copper wire has the length 34.5m and the radius 0.25mm at 20.0°C . Potential difference across between ends of wire is 9.0V , The copper wire has the length 34.5m and the radius 0.25mm at 20.0°C . Potential difference across between ends of wire is 9.0V

Explanation:

Formula to calculate the resistance of copper wire is,

R0=ρLA

• R0 is the resistance of copper wire at 20.0°C
• ρ is the resistivity of copper,
• A is the area of cross section of copper wire,
• L is the length of copper wire,

Area of circular cross section of wire is given by

A=πr2

• r is the radius of the wire

Substitute equation for area in the previous equation to rewrite R0 .

R0=ρL(πr2)

Substitute 1.7×108Ωm for ρ , 34.5m for L , 3.14 for π , and 0.25mm for r in the above equation to find ρ

(b)

To determine
The current passing through the copper wire at 30.0°C

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Find more solutions based on key concepts 