Heat Flowing Through A Sectioned Rod HELP

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SUMMARY

The discussion focuses on calculating the heat transfer through a sectioned rod made of copper and steel, with specific thermal conductivities of 385 W/m·K for copper and 50.2 W/m·K for steel. The rod is insulated, with one end in boiling water and the other in an ice-water mixture, resulting in a junction temperature of 65.0°C. The correct formula for heat transfer, H = k * A * (ΔT) / L, is applied, and the area must be converted from cm² to m² for accurate calculations. The final heat transfer rate calculated for the copper section is 21.56 W, which was initially miscalculated due to incorrect area units.

PREREQUISITES
  • Understanding of thermal conductivity and heat transfer principles
  • Familiarity with the formula H = k * A * (ΔT) / L
  • Knowledge of unit conversions, specifically area from cm² to m²
  • Basic concepts of steady-state heat transfer in composite materials
NEXT STEPS
  • Review the derivation and applications of the heat transfer equation H = k * A * (ΔT) / L
  • Learn about thermal conductivity values for various materials and their implications in engineering
  • Study the effects of insulation on heat transfer in practical applications
  • Explore numerical methods for solving heat transfer problems in composite materials
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Students studying thermodynamics, engineers working with thermal systems, and anyone involved in heat transfer analysis in materials science.

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Homework Statement



A long rod, insulated to prevent heat loss along its sides, is in perfect thermal contact with boiling water (at atmospheric pressure) at one end and with an ice-water mixture at the other. The rod consists of a 1.00 section of copper (with one end in the boiling water) joined end-to-end to a length of steel (with one end in the ice water). Both sections of the rod have cross-sectional areas of 4.00 . The temperature of the copper-steel junction is 65.0 after a steady state has been reached.
How much heat per second flows from the boiling water to the ice-water mixture?
Express your answer in watts

Homework Equations



H=kAdT/L
kcopper=385
ksteel=50.2

The Attempt at a Solution



Hcopper=Hsteel
Hcopper=385*0.04^2*35
= 21.56W
There's something wrong with this answer.. Can someone please help me?
Thank you!
 
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Hi tizzful,

In your expression you have squared 0.04 (which is (area/length) in meters); since they gave the area I don't believe that number should be squared.
 
Hello, yes I realized afterwards that its in cm squared and I need it in meters squared and therefore had to multiply it by 10^-4. Thank you
 

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