A particle of charge +q and mass m is in a uniform magnetic field $B=B_0\widehat{z}.$  The initial position of the particle is $x=0,y=0,z=0$, the magnitude of the momentum of the particle is  $p_0$. The particle is so projected that it crosses the point  $[x=\frac{p_0}{q{B}_0},y=0,z=0]$. What is the time (in sec) after which it reaches this point ? Take $\frac{m}{q}=\frac{12}{\pi }SI$ units and  $B=0.2T.$