A particle of charge -16 x10-18C moving with velocity 10 m/s along the X-axis enters a region where a magnetic field of induction B is along Y-axis and electric field of magnitude 104 V/m is a. long the negative Z-axis. If the charged particle continues moving along the X-axis, the magnitude of B is

The situation is shown in fig .We know that,F= q (E+ V x B)or F = qE + q (v x B)Now Fe = gE=−16×10−18×104(−k)=16×10−14kAnd Fm=−16×10−18(10i×Bj)=−16×1017B(k)∴ F=Fe+Fm=16×10−14k−16×10−17BkSince, the particle will continue to move along +X-axis, so resultant force is zero. Therefore, Fe + Fm = 0or 16×10−14k=16×10−17Bk∴ B=103Wb/m2