a) Discuss how Gauss's law for magnetic fields differs from Gauss's law for electric fields and why? (4 marks) b) Explain how Biot-Savart law is used to derive the magnetic field of a straight wire carrying a current I. Support your answer with illustrative diagrams. (5 marks) c) A 40 A current flows through a straight wire from (−3,4,3) to (3,4,3). Find the magnetic field intensity and m ynetic flux density at (0,0,3). (8 marks) d) Two circular loops carrying equal current of 10 A are arranged vertically on top of each other. The first loop is situated in the xy-plane with its centre at the origin and its current is clockwise. The second loop is parallel to the xy-plane with its centre 2 m above the origin and its current is anticlockwise. If both loops have the same radius r=3 m, determine the magnetic field at the (0,0,2).