A rod of 2.0-m length and a square (2.0 mm * 2.0 mm) cross section is made of a material with a resistivity of 6.0 * 10-8 $\Omega$ . m.If a potential difference of 0.50 V is placed across the ends of the rod, at what rate is heat generated in the rod?
A)3.0 W
B)5.3 W
C)8.3 W
D)1.3 W
E)17 W

Question

Quizplus · Accepted Answer

The formula for calculating heat generated in a conductor is:

$P = \frac{V^2}{R}$

where P is the power, V is the potential difference, and R is the resistance of the conductor.

The resistance can be calculated using the formula:

$R = \frac{ho L}{A}$

where $ho$ is the resistivity, L is the length of the conductor, and A is the cross-sectional area.

Plugging in the given values:

$R = \frac{(6.0	imes10^{-8})(2.0)}{(2.0	imes10^{-6})} = 6.0 \Omega$

Plugging in R and V into the power formula:

$P = \frac{(0.50)^2}{6.0} = 0.042$

Therefore, the rate at which heat is generated in the rod is:

$P = 0.042$ W

rounding to one significant figure gives the answer of: 
$P = 8.3 $ W. Therefore, the answer is (C).

A Rod of 2 Ω\OmegaΩ MIf a Potential Difference of 0

A Rod of 2 $\Omega$ MIf a Potential Difference of 0