JEE Main 2019 — Thermal Properties of Matter Question with Solution
JEE Main 2019 (12 Jan Shift 1)
Question
A cylinder of radius is surrounded by a cylindrical shell of inner radius and outer radius . The thermal conductivity of the material of the inner cylinder is and that of the outer cylinder is . Assuming no loss of heat, the effective thermal conductivity of the system for heat flowing along the length of the cylinder is:
Choose an option
Show full solutionCorrect option: D
Correct answer
D
Step-by-step explanation
Let and be the rate of flow of heat through inner part from outer part respecting net flow of heat
If the cylinder is replaced by a single material of thermal conductivity then
On comparison,
.
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This is a previous-year question from JEE Main 2019, covering the Thermal Properties of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.