Question

Biot-Savart law indicates that the moving electrons (velocity $\overline{v}$ ) produce a magnetic field $\overline{B}$ such that:

• A. $\overline{B}\perp \overline{v}$
• B. $\overline{B}\parallel \overline{v}$
• C. it obeys inverse cube law.
• D. it is along the line joining the electron and point of observation.

Answer 1

The correct option is A $\overline{B}\perp \overline{v}$

Magnetic field produced by charges moving with velocity $\overline{v}$, at a distance r is $\overline{B}$ = $\left(\frac{{\mu }_0}{4\pi }\right)$.q$\frac{\overline{v}\times \hat{r}}{r^2}$
Therefore $\overline{B}\perp \overline{v}$