Question

What is the length of an iron rod (k = 79 J/s*m* C°) with cross-sectional area 0.060 m² that takes 40 s to conduct 2.5 kJ of heat when the temperature difference between its two ends is 80 C°?

A. 6.1 m
B. 2.0 m
C. 4.1 m
D. 8.2 m

Answer 1

The length of the iron rod is 4.1 meters.

Step-by-step explanation:

To find the length of an iron rod, we can use the formula for heat conduction given by Q = kAΔT / L, where Q is the amount of heat transferred, k is the thermal conductivity of the iron rod, A is the cross-sectional area of the rod, ΔT is the temperature difference, and L is the length of the rod.

Plugging in the known values, we have 2.5 kJ = (79 J/s*m*C°)(0.060 m²)(80 C°) / L. Solving for L, we get L = (79 J/s*m*C°)(0.060 m²)(80 C°) / (2.5 kJ) = 4.1 m.

Therefore, the length of the iron rod is 4.1 meters.