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CUET · PHYSICS · PYQ PAPER 2025

The ratio of lengths of two wires is 2 : 3 and the ratio of their resistivities is 3 : 2. If they have the same resistance then the ratio of their respective diameters is

  1. A \(4: 9\)
  2. B \(9: 4\)
  3. C \(\sqrt{2}: \sqrt{3}\)
  4. D \(1: 1\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(1: 1\)

Step-by-step Solution

Detailed explanation

\(R = \frac{\rho L}{A} = \frac{4\rho L}{\pi d^2}\) \(R_1 = R_2 \Rightarrow \frac{\rho_1 L_1}{d_1^2} = \frac{\rho_2 L_2}{d_2^2}\) \(\frac{d_1^2}{d_2^2} = \frac{\rho_1}{\rho_2} \times \frac{L_1}{L_2}\)…