The principle of the velocity selector is based on mutually

The principle of the velocity selector, is based on mutually perpendicular E, B and u . Obtain an expression for the required speed for particles to pass through. A charged particle moves with a uniform velocity 25.0 x m/s in a region where E = 40.0 y v/m. If B = B_0z Wb/m^2 determine B_0 such that the velocity of the particle remains constant.

Solution

a) there will be two forces acting on the charged particle one due to the electric field and the other due to magnetic field. both of the force are acting opposite to each other.

so in order to pass through q*E = q*u*B

b) q*40 = q*25*B

so B = 40/25 = 1.6