AP and TS EAMCET Medical Model Paper 10

(4)Particle moves without any deflection with same speed when no force acts on it.
Case (i): Both electric, magnetic fields are zero.
So force on particle is zero.
Case (ii): If forces due to electric and magnetic fields are equal and opposite, it can travel without deflection.
Case (iii):FB = BQv sin θ. Hence if θ = 90°, force due to magnetic field becomes zero.
Case (iv): If E ≠ 0, a force will act due to electric field and its speed changes.