Question

A copper rod of cross-sectional area $A$ carries a uniform current $I$ through if. At temperature $T$, if the volume charge density of the rod is $\rho$, how long will the charges take to travel a distance $d$?

• A. $\frac{2\rho dA}{IT}$
• B. $\frac{2\rho dA}{I}$
• C. $\frac{\rho dA}{I}$
• D. $\frac{\rho dA}{IT}$

Answer 1

Answer: (C)

$\frac{\rho dA}{I}$

$I=\rho vA$ ($v=$ velocity of charge)

$v=\frac{I}{\rho A}$

$t=\frac{d}{v}$

$t=\frac{\rho dA}{I}$