A physics team investigates heat conduction through an aluminum bar of fixed…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A physics team investigates heat conduction through an aluminum bar of fixed cross-sectional area. They record the steady-state energy transfer rate R for several imposed temperature differences ΔT across a bar of length L0=0.30m. Their data are shown below.
ΔT (∘C)
R (J s−1)
10
1.2
20
2.4
30
3.6
40
4.8
Later, the same team repeats the experiment with a bar of identical material and cross-sectional area but length 2L0, again using several temperature differences.
(a) Using the data for length L0, determine the numerical relationship between R and ΔT and state the proportionality constant (slope) obtained from the table.
(b) Predict, without additional calculation, the slope the team should obtain when plotting R versus ΔT for the bar of length 2L0. Explain your reasoning.
(c) If the team actually measures a slope that is 5% lower than your prediction in part (b), list two plausible experimental factors that could account for the discrepancy.