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CUET · PHYSICS · PYQ PAPER 2025

Two resistance wires are of same material having length, l and 2l and area of cross-section, 4A and A respectively. When they are connected in parallel, their equivalent resistance can be expressed as

  1. A \( \frac{2}{9} \left( \rho \frac{l}{A} \right) \)
  2. B \( \frac{4}{9} \left( \rho \frac{l}{A} \right) \)
  3. C \( \frac{9}{2} \left( \rho \frac{l}{A} \right) \)
  4. D \( \frac{9}{4} \left( \rho \frac{l}{A} \right) \)
Verified Solution

Answer & Solution

Correct Answer

(A) \( \frac{2}{9} \left( \rho \frac{l}{A} \right) \)

Step-by-step Solution

Detailed explanation

\( R_1 = \rho \frac{l}{4A} \) \( R_2 = \rho \frac{2l}{A} \) \( R_{eq} = \frac{R_1 R_2}{R_1 + R_2} = \frac{(\rho \frac{l}{4A})(\rho \frac{2l}{A})}{\rho \frac{l}{4A} + \rho \frac{2l}{A}} \)…