A 0.20-m-long metal rod has a radius of 3.0 cm and a resistance of 2.5 × 10−⁵ Ω.What is the resistivity of the metal?

Question

Quizplus · Accepted Answer

The resistivity ($\rho$) of the metal can be calculated using the formula for resistance ($R$) of a cylindrical conductor: $R = \frac{\rho L}{A}$, where $L$ is the length of the conductor and $A$ is its cross-sectional area. The area $A$ of the rod can be calculated using the formula for the area of a circle, $A = \pi r^2$, where $r$ is the radius of the rod. Given that the radius $r = 3.0 \, \text{cm} = 0.03 \, \text{m}$, the area $A = \pi (0.03)^2 \, \text{m}^2$. Substituting the given values and solving for $\rho$, we find that the resistivity of the metal matches the value given in option B.

A 020-M-Long Metal Rod Has a Radius of 3