A current I= 4.0 A flows along a straight wire on the axis of a long cylindrical tube, which has internal radius a= 2.0 cm, external radius 2a, and is made of an LIH magnetic material with relative permeability u - 5.0, as shown below. 2a Derive an expression in terms of I, u and a for the bound surface current per unit length ib on the inner surface of the tube due to its magnetization, and hence calculate the magnitude i of this surface current per unit length and specify the direction in which this current flows. Give your answers by entering a number in the expression below for the magnitude i and selecting the direction from the list of cylindrical unit vectors. |Am-1 Direction of ib: O+er O-er O +eo O-eo O +e: O-ez

A current I= 4.0 A flows along a straight wire on the axis of a long cylindrical tube, which has internal radius a= 2.0 cm, external radius 2a, and is made of an LIH magnetic material with relative permeability u - 5.0, as shown below. 2a Derive an expression in terms of I, u and a for the bound surface current per unit length ib on the inner surface of the tube due to its magnetization, and hence calculate the magnitude i of this surface current per unit length and specify the direction in which this current flows. Give your answers by entering a number in the expression below for the magnitude i and selecting the direction from the list of cylindrical unit vectors. |Am-1 Direction of ib: O+er O-er O +eo O-eo O +e: O-ez