An electron moves along a vertical line and away from the observer. What is the pattern of the concentric circular magnetic field lines produced due to its motion?

Magnetic field at a distance $r$ from an infinitely long straight conductor carrying a steady current varies as

$A$ long straight wire carrying current $16 \,A$ is bent at $90^{\circ}$ such that one segment lies along the positive $x$-axis and the other segment lies along the positive $y$-axis. What is the magnitude of the magnetic field at the point $P(-2 \,mm, 0)$ (in $\,mT$)? (Assume $\frac{\mu_0}{4 \pi} = 10^{-7} \,T \cdot m/A$)

$A$ current $i$ is flowing through the loop. The direction of the current and the shape of the loop are as shown in the figure. The magnetic field at the centre $M$ of the loop is $\frac{\mu_{0} i}{R}$ times
$(MA=R, MB=2 R, \angle DMA=90^{\circ})$

$A$ long straight wire carrying a current of $30 \ A$ is placed in an external uniform magnetic field of induction $4 \times 10^{-4} \ T$. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point $2.0 \ cm$ away from the wire is $(\mu_0 = 4 \pi \times 10^{-7} \ H/m)$.

Two concentric coils each of radius equal to $2\pi \text{ cm}$ are placed at right angles to each other. If $3 \text{ A}$ and $4 \text{ A}$ are the currents flowing through the two coils respectively,the magnetic induction (in $\text{Wb m}^{-2}$) at the centre of the coils will be: