force=q*v*b*sin(theta) for (a) q = 1.6*10^-19; v = 1*10^7; b = 0.5 T along x axis;theta = 45 force comes out to be 0.56*10^-12..now apply swrew rule.u will find the force is in y direction.bring it to z and x componet by the formula force*cos(theta)..since angle between coordinate axis is 90 degree so there is no x or z componet of force. thus force is 0x+0.56*10^-12y+0z = 0.56*10^-12y
for (b) theta is equal to 180 degree and all other r same so force comes out to be 0.there is thus no Fx or Fy or Fz
