Chapter 29, Problem 4EAP

An electron moves along the z-axis with $v_z=2.0\times {10}^7$ m/s. As it passes the origin, what are the strength and direction of the magnetic field at the (x, y. z) positions (a) $\left(\text{1 cm}.0\text{cm}.0\text{ cm}\right)$ , (b) $\left(0\text{ cm},0\text{ cm},\text{ 1 cm}\right)$ , and (C) $\left(0\text{ cm},\text{ 1 cm},\text{ 1 cm}\right)$ ?