A charge having q/m equal to $10^8$ c/kg and with velocity $3 × 10^5$ m/s enters into a uniform magnetic field $B = 0.3$ tesla at an angle $30^{\circ}$ with direction of field. Then radius of curvature will be :

Question

( A ) 2 cm
( B ) 1 cm
( C ) 0.01 cm
( D ) 0.5 cm