A point charge is moving in clockwise direction in a circle with constant spee(d) Consider the magnetic field produced by the charge at a fixed point P (not at the center of circle) on the axis of the circle. Then,

he magnetic field at a point on the axis due to charge moving along a circular path is given by $\frac{{\mu }_0}{4\pi }\frac{q\overrightarrow{v}\times \overrightarrow{r}}{r^3}$' It can be seen that the magnitude of the magnetic field at a point on the axis remains constant. But direction of the field keeps on changing.