A positive charge enters a region of perpendicular electric and magnetic fields as shown in the figure, travelling with speed V₀ directed horizontally to the right. Initially the charge moves through the region shown with no deflection and emerges through the hole in screen S₂. If we now want the charge to hit below the hole in the screen S₂ we should not :-

Question

G1 Physics · Accepted Answer

Initially qE=qv₀B. If v is reduced or E increased, electric force dominates in the direction that bends the positive charge upward; to hit below, magnetic force must dominate, achieved by increasing v or decreasing E. Therefore the actions that should not be used are those in B,C,D, matching the key.