Resistance Physics Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium
A wire has length 2ย m2 \text{ m}, cross-sectional area 1ร—10โˆ’6ย m21 \times 10^{-6} \text{ m}^2, and resistivity ฯ=1.7ร—10โˆ’8ย ฮฉโ‹…m\rho = 1.7 \times 10^{-8} \text{ } \Omega \cdot \text{m} (copper). What is its resistance?

Solution

  1. 1
    Use the resistance formula: R=ฯLAR = \frac{\rho L}{A}.
  2. 2
    Substitute the given values: R=1.7ร—10โˆ’8ร—21ร—10โˆ’6=3.4ร—10โˆ’81ร—10โˆ’6R = \frac{1.7 \times 10^{-8} \times 2}{1 \times 10^{-6}} = \frac{3.4 \times 10^{-8}}{1 \times 10^{-6}}.
  3. 3
    R=0.034ย ฮฉR = 0.034 \text{ } \Omega

Answer

R=0.034ย ฮฉR = 0.034 \text{ } \Omega
Resistance depends on the material (resistivity), length, and cross-sectional area. Longer wires have more resistance; thicker wires have less.

About Resistance

A measure of how strongly a material opposes electric current, measured in ohms (ฮฉ\Omega) โ€” higher resistance means less current for a given voltage.

Learn more about Resistance โ†’

More Resistance Examples

Example 1 easy

A resistor carries [formula] of current when [formula] is applied across it. What is the resistance?

Example 3 easy

If the resistance of a wire doubles and the voltage stays the same, what happens to the current?

Example 4 medium

A wire has resistance [formula]. If you replace a wire with one that is twice as long and has three

โ† All Resistance Examples Resistance Concept