Write the expression for the magnetic force acting on a, charged particle moving with velocity v in the presence of magnetic field B.

(a) Write the expression for the magnetic force acting on a k charged particle moving with velocity v in the presence of magnetic field B . (b) A neutron an electron and an alpha particel moving with equal velocities enter a uniform magnetic field going into the plane of the paper as shown. Trace their paths in the field and justify your answer .

Write the expression for the magnetic force vecF acting on a charged particle q moving with vec upsilon in the presence of the magnetic field vec B in a vector form. Show that no work is done and no charge in the magnitude of the velocity of the particle is produced by this force. Hence define the unit of magnetic field.

Write the expression for the force vecF , acting on a charged particle of charge q moving with a velocity vecv in the pressure of both electric field vecE and magnetic field vecB . Obtain the condition under which the particle moves undeflected through the fields.