we discussed a charged particle moving through crossed fields with the forces F_E and F_B in opposition. We found that the particle moves in a straight line (that is, neither force dominates the motion) if its speed is v = E/B. Which of the two forces dominates if the speed of the particle is v E/B? F_E F_B

Magnetic force = Bqv

Electric force = E q

Magnetic force = electric force

Bqv = Eq

v = E / B

If v is less than E / B, magnetic force will become feeble because magnetic force is dependent on velocity of charged particle. (magnetic force = Bqv)

Contrary to it, if v is more than E / B magnetic force will become stronger.