Question

An electric current passes through non-uniform crosssection wire made of homogeneous and isotropic material. If $j_{A}$ and $j_{B}$ are the current densities and $E_{A}$ and $E_{B}$ are the electric field intensities at $A$ and $B$ respectively, then

• A. $j_{A} > j_{B} ; E_{A} > E_{B}$
• B. $j_{A} > j_{B} ; E_{A} < E_{B}$
• C. $j_{A} < j_{B} ; E_{A} > E_{B}$
• D. $j_{A} < j_{B} ; E_{A} < E_{B}$

Answer 1

Answer: (A)

$\frac{I}{A}=j$ and $j=\frac{E}{\rho}$
$\therefore j_{A} > j_{B}$ and $E_{A} > E_{B} .$