A current of I = 3.8 A is passing through a conductor with cross sectional area A = 2.5 x 10^-4 m^2. The charge carriers in the conductor, electrons, have a number density n = 1.3 x 10^27 m^-3.
(a) Express the drift velocity of electrons through 1.A. n, and the fundamental charge e.
(b) Calculate the numerical value of v, in m/s.

Acyclotron is used to produce a beam of high-energy deuterons that then collide with a target to produce radioactive isotopes for a medical procedure. deuterons are nuclei of deuterium, an isotope of hydrogen, consisting of one neutron and one proton, with total mass 3.34×10−27kg. the deuterons exit the cyclotron with a kinetic energy of 6.40 mev .a-what is the speed of the deuterons when they exit? b-if the magnetic field inside the cyclotron is 1.25 t, what is the diameter of the deuterons' largest orbit, just before they exit? c-if the beam current is 350 μa how many deuterons strike the target each second?