In the following figure a beam of electrons is fired into the region of crossed electric and magnetic fields. E-intensity of electric field : B-magnetic induction field strength. If the velocity of the electron beam , v>EB, then

force due to electric field eE is upward and due to magnetic field evB is downwardif eE= evB then it will go undeviated  then v=EBv is more than EB then force due to magnetic field will be stronger so it will get deflected downward