Problem1: (15 points) Use the Bio:-Savart to calculate the magnetic field on the axis of a tightly wound solenoid (helical coil) consisting of n" turns per unit length wrapped around a of lindrival tube of radius "a and with current "/ in it (see figure below). Express your answer only in terins of the given quantities "a", " U.", "0,", and fundamental constants . Consider the turns of this finite solenoid to be circular. Hint. Start with the expression for the magnetic field generated by a circular current loop discussed in section 28.5 of the textbook}. P