[2019EM/QUIZ-05]

Electrodynamics                                                    Mar 18, 2019

                                        Quiz-V 

1. Eight wires cut the paper perpendicularly at the points shown in figure below. A wire labeled with integer $k$ ($k$=1,2,\ldots,8) carry currents $I_k$ as given below. For those with odd $k$ the current flows up out of the paper; for those with even $k$ the current flows down into the paper. Write an expression for $\oint \vec{B}\cdot\vec{dl}$ along the closed path shown in the direction by a single arrowhead. Find the value of the line integral when the eight currents, $I_1,I_2,\ldots,I_8$, have the values 1,2,..,8 amp, respectively
2. Four long copper wires are held parallel to each other, their cross section forming a square of $2$\,cm on edge. A current of $5$\,amp is set up in each wire in direction shown in Fig.2 below. Find the magnitude and the direction of $\vec{B}$ at the center of the square?