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MHT CET · Physics · Thermal Properties of Matter

The ratio of thermal conductivity of two rods \(\mathrm{A}\) and \(\mathrm{B}\) with the same area of cross-section is \(3: 2\). If the thermal resistance of two rods is the same, then the ratio of length of rod A to length of rod B is

  1. A \(3: 2\)
  2. B \(2: 3\)
  3. C \(5: 1\)
  4. D \(1: 5\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(3: 2\)

Step-by-step Solution

Detailed explanation

Given \(A_1=A_2\) and \(\frac{K_1}{K_2}=\frac{3}{2}\)
If thermal resistance is equal
\(R_1=R_2 \Rightarrow \frac{l_1}{K_1 A_1}=\frac{l_2}{K_2 A_2} \Rightarrow \frac{l_1}{l_2}=\frac{K_1}{K_2}=\frac{3}{2}\)