Q. A conductor wire having $10^{29}$ free $electrons/m^{3}$ carries a current of 20A. If the cross-section of the wire is $1{mm}^{2}$, then the drift velocity of electrons will be
A) $6.25 \times 10^{- 3}{ms}^{- 1}$
B) $1.25 \times 10^{- 5}{ms}^{- 1}$
C) $1.25 \times 10^{- 3}{ms}^{- 1}$
D) $1.25 \times 10^{- 4}{ms}^{- 1}$
Explanation
(c) $v_{d} = \frac{I}{nAe} = \frac{20}{10^{29} \times 10^{- 6} \times 1.6 \times 10^{- 19}} = 1.25 \times 10^{- 3}m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.