The basic principle underlying the hall effect is the Lorentz force. Whenk an electron moves along a direction perpendicular to an applied magnetic field. It exeriences a force acting normal to both the directions and moves in response to this force and the force exerted by the internal electric field. For an - n-type bar shaped semiconductor, the carries are predominatly electrons of bulk density n. We assume that the constant current I flows along the x-axis from left to right in the presence of a magnetic field toward the negative z-axis resulting in an excess surface electrical charge on the sides of the sample. this charge results in the hall voltage a potential drop across the two sides of the sample Thre transverse voltage is the hall voltage V_(H) and its magnitude is equal to IB/qnD, where I is the current B is the magnetic field, d is the sample thickness and q is the elementary charge. A silver ribbon lies as shown in the adjacent figure (z_(1) = 11.8 mm and = 0.23 mm) carrying a current of 120 A in the x -direction inunifrom magnetic field B = 0.95 T. If electron density is 5.85 xx 10^(28)//m^(3) then magnitude of the drift velocity of electron is