The magnetic field at a perpendicular distance of $1 \,m$ from a long straight wire carrying a current of $1 \,A$ is:

The intensity of the magnetic induction field at the centre of a single turn circular coil of radius $5 \,cm$ carrying a current of $0.9 \,A$ is:

Two long current-carrying conductors are placed parallel to each other at a distance of $8 \, cm$ between them. The magnitude of the magnetic field produced at the mid-point between the two conductors due to the current flowing in them is $300 \, \mu T$. The equal current flowing in the two conductors is ...............

The magnetic field at the origin due to a current element $i d l$ placed at a point with vector position $r$ is

Current $I$ is flowing in a conductor shaped as shown in the figure. The radius of the curved part is $r$ and the length of the straight portions is very large. The value of the magnetic field at the centre $O$ will be

Two identical long current-carrying wires are bent into the shapes shown in the figures. If the magnitudes of the magnetic fields at the centers $P$ and $Q$ of the quarter-circular arcs are $B_1$ and $B_2$ respectively, then the ratio $\frac{B_1}{B_2}$ is: