Question

Suppose a wire is kept vertical, through which current $i=5\sqrt{2}\sin \omega t\text{A}$ is flowing. A uniform magnetic field of $4.5\text{mT}$ exist in horizontal direction. The average magnetic force $\left(\text{in N}\right)$ on the wire in a complete cycle of current will be (Integer only)

Answer 1

We know that, magnetic force on a current carrying wire is given by,

$\overrightarrow{F}=I(\overrightarrow{l}\times \overrightarrow{B})$

Here, length of wire $l$ and magnetic field $B$ is independent of time.

So, average magnetic force depends on average value of current.

And we know that the average value of current for a sinusoidal function is zero in a full cycle.

Hence, average magnetic force on the wire is zero for a full cycle of current.