Question

Calculate the drift velocity of free electrons if a current of 200 A is maintained in a conductor of cross-section 10^-3m^2. The number density of free electrons is 96 × 10^20 m^-3.

(a) 130.20 ms^-1

(b) 13.020 ms^-1

(c) 1.3020 ms^-1

(d) 0.1302 ms^-1

I have been asked this question by my college director while I was bunking the class.

Query is from Current Electricity topic in portion Current Electricity of Physics – Class 12

Answer 1

Right option is (a) 130.20 ms^-1

Explanation: Drift velocity = \(\frac {Current}{(number \, density \, of \, electrons \, \times \, charge \, on \, electron \, \times \, Area)}\).

=\(\frac {200}{(96 \times 10^{20} \times 1.6 \times 10^{-19} \times 10^{-3})}\)

= 130.20 ms^-1.