​ A positively charged particle enters a magnetic field of value B \widehat{i} with a velocity v \widehat{j}

A positively charged particle enters a magnetic field of value B \(\widehat{i}\) with a velocity v \(\widehat{j}\) then the instantaneous direction of particle will be along(a) Z- axis(b) − Z- axis(c) − X- axis(d) − Y- axis

Answer is : (b) − Z- axis Force on the charged particle in magnetic field is F = q(v  \(\widehat{j}\) x B \(\widehat{i}\) ) = qvB(- \(\widehat{k}\) ) which is - Z- axis.