A charge of $+10\mu C$  and mass of 1gm is moving with velocity of 10⁶ m/s at an angle of 45° to x & y axis as shown. In this case it experiences a magnetic force along – ve z – direction. If it were projected with ${10}^{6}m/s$  along +ve z – direction, it would experience a magnetic force of ${10}^{–2}N$  in +ve x-direction. The magnetic field $\overrightarrow{B}$   is: