Mysteriously a charged particle moving with velocity $$\overrightarrow{v} = v_0 i$$ entered the tube of Thomson's apparatus where the parallel metallic plates of length 5 cm along X axis are separated by 2 cm. Under the influence of a magnetic field of magnitude $$ \overrightarrow{B} = 4.57\times 10^{-2}$$ T, the particle is found to deflect by an angle of $$5.7^\circ$$. When a potential of 2000 volt is applied between the two plates, the particle is found to move straight to the screen without any deflection. Then,