A straight conductor of uniform cross section carries a time varying current, which varies at the rate `di//dt = I`. If `s` is the specific charge that is carried by each charge carrier of the conductor and l is the length of the conductor, then the total force experienced by all the charge carrier per unit length of the conductor due to their drift velocities only is

Options

A. I s
B. `(I)/(s)`
C. `sqrt((I)/(s))`
D. `((I)/(s))^2`

Answer

B

Explanation

`I = n e A v_d, s = ( e)/(m)`
Momentum of all free electrons//length
`p = ((nAl)mv_d)/(l) = (n A ev_d m)/(e)`
=`(n e Av_d)/(e//m) = (I)/(s)`.