A very fine wire is tightly wound around a long coil to form a solenoid. If the inner radius of the coil is a. A current / flow through the coil and the coil has a length of /. 1.1 Show that the magnetic flux density inside the coil is given by nl, where n is the number of turns per unit length 1.2 Calculate the magnetic flux in the solenoid. 1.3 Repeat the above calculations but assume the coil is wound around a magnetic material met relative permeability of 4,. 1.4 Calculate for 1.3 the magnetization vector M, as well as the bound current densities.