A wire oriented in the east-west direction carries a current eastward. Direction of the magnetic field at a point to the south of the wire is

 

In the adjacent figure, Fig.$8.118,$ is shown a closed path $P$. A long straight conductor carrying a current $I$ Passes through $O$ and perpendicular to the plane of the paper. Then which of the following holds good ?

A cell is connected between the points $A$ and $C$ of a circular conductor $ABCD$ with $O$ as centre Fig. $8.119$ and angle $AOC=60°.$ If $B_1$ and $B_2$ are the magnitudes of the magnetic fields at $O$ due to the currents in $ABC$ and $ADC$ respectively, then ratio $\frac{B_1}{B_2}$ is 

In the figure Fig.$8.120$ show, the magnetic field induction at the point $O$ will be