ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2025

A copper wire of area of cross-section \( 2 \times 10^{-6} \, \text{m}^2 \) and electron density \( 10^{28} \, \text{m}^{-3} \) carries a current of 1.6 A. Time taken by an electron to drift from one end of a 1.0 m long wire to its other end will be

  1. A \( 2 \times 10^3 \, \text{s} \)
  2. B \( 10^3 \, \text{s} \)
  3. C \( 2 \times 10^{-3} \, \text{s} \)
  4. D \( 1 \times 10^{-3} \, \text{s} \)
Verified Solution

Answer & Solution

Correct Answer

(A) \( 2 \times 10^3 \, \text{s} \)

Step-by-step Solution

Detailed explanation

\( v_d = \frac{I}{nAe} = \frac{1.6}{10^{28} \times 2 \times 10^{-6} \times 1.6 \times 10^{-19}} = 5 \times 10^{-4} \, \text{m/s} \) \( t = \frac{L}{v_d} = \frac{1.0}{5 \times 10^{-4}} = 2 \times 10^3 \, \text{s} \)
Same subject
Explore more questions on app