If magnetic field at point $O$ is zero then find out the value of $\theta$ (in radian).

 

A conductor carrying a current, $I$ is shown in the figure. Calculate the magnetic field intensity at the point $O$ (common center of all three arcs). Use $I=2 \mathrm{A}, \theta =48 \mathrm{rad}$ and $r=2\mu \mathrm{m}$

Calculate $B\times {10}^5$, where $B$ is magnetic field (in SI unit) at point '$O$' of current distribution, where $I=3.14\mathrm{A}$ and $r=6.28\mathrm{cm}$

Six wires of current $I_1=1\mathrm{A}, I_2=2\mathrm{A}, I_3=3\mathrm{A},I_4=1\mathrm{A},I_5=5\mathrm{A}$ and $I_6=4\mathrm{A}$ cut the page perpendicularly at the points $1,2,3,4$ and $6$ respectively as shown in the figure. Find the magnitude of the integral $\frac{\oint \overrightarrow{B}·d\overrightarrow{l}}{{\mu }_0}$ around the closed path.

Calculate magnetic moment (in SI unit) of shown system. (Use$q=6 \mathrm{C}, \omega =10 \mathrm{rad} {\sec }^{-1}$ and $l=1 \mathrm{m}$)

A straight wire of length $l$ carries current $I$ is moulded in the form of semicircular loop then its magnetic moment (in SI unit) is $x\times {10}^{-1}$, where $I=2\mathrm{A}$ and $l=4\mathrm{m}$. Write the value of $x$ to the nearest integer.