The resistivity of a 1.0 m long wire is 1.72 × 10^-8 Ωm and its cross sectional area is 2.0 × 10^-6 m². If the wire carries a current of 0.20 A, what is the voltage across the wire? A) 17 mV B) 0.90 mV C) 1.7 mV D) 10 mV E) 90 mV

Question

Quizplus · Accepted Answer

The resistance of the wire can be calculated using the formula:

R = ρL/A

where ρ is the resistivity, L is the length of wire, and A is the cross-sectional area.

R = (1.72 × 10^-8 Ωm)(1.0 m)/(2.0 × 10^-6 m^2) = 8.6 Ω

Using Ohm's Law (V = IR), we can find the voltage across the wire:

V = IR = (0.20 A)(8.6 Ω) = 1.72 V

However, the question asks for the voltage in millivolts (mV), so we need to convert:

1.72 V = 1720 mV

Therefore, the answer is 1.7 mV, which is choice C.

The Resistivity of a 1