Two charged particles having charge of same magnitude, but opposite sign and same mass.
Since they are prjected in opposite direction the direction of deflection is same. Hence they will travel in a circular motion as shown in figure (v1 > v2).
angular momentum of charged particle moving in magnetic field is given by L = m × v × r , where r is radius of curvature
radius of curvature can be obtained from q×B×v = m(v2/r).
Hence L = m × v × [ mv/ (qB) ] = m2v2 / (qB)
velocity of Particle-B with respect to particle-A is v2-v1.
Hence angular momentum of particle-B with respect to particle-A is
angular momentum of particle-B with respect to particle-A is proportional to