ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2025

Two wires A and B of the same material and same mass have radii 2r and r, respectively. If the resistance of wire A is \( 4 \, \Omega \), then resistance of B will be

  1. A 64 \( \Omega \)
  2. B 4 \( \Omega \)
  3. C 32 \( \Omega \)
  4. D 16 \( \Omega \)
Verified Solution

Answer & Solution

Correct Answer

(A) 64 \( \Omega \)

Step-by-step Solution

Detailed explanation

\( R = \frac{\rho m}{d \pi^2 r_{wire}^4} \) \( \frac{R_B}{R_A} = \left( \frac{r_A}{r_B} \right)^4 \) \( \frac{R_B}{4 \, \Omega} = \left( \frac{2r}{r} \right)^4 \) \( R_B = 4 \, \Omega \times (2)^4 = 4 \, \Omega \times 16 = 64 \, \Omega \)