Question

A straight conductor of uniform cross-section carries a current, $I$. If ${}^{\prime }{s}^{\prime }$ is the specific charge of an electron, the momentum of all the free electrons per unit length of the conductor, due to their drift velocity only, is

• A. $Is$
• B. $\sqrt{\frac{I}{s}}$
• C. $\frac{I}{s}$
• D. ${\left(\frac{I}{s}\right)}^2$

Answer 1

The correct option is C $\frac{I}{s}$

$V_d=\frac{I}{neA}$

total mass $=m_e\times n\times A$

$P=m{V}_d$

$=\frac{I}{neA}\times m_{e}nA$

$=\frac{I}{e/m_e}=\frac{I}{S}$