Question 5 3. 21 -axis V-axis 2a x-axis Figure 3 : Three circular loops on some sides of an imaginary cube. (The cube drawn is only to help you visualize the position of the loops) (a) Look in your notes and recall the expression for the magnetic field along the axis of a circular current-carrying loop. (b) Three current-carrying circular loops, each of radius a, are placed on three faces of an imaginary cube of side 2a. The cube has one corner at origin O. See Figure 3. The loop in plane x = 2a carries current /; the loop in plane y= 2a carries current 2/ and the loop in plane z = 2a carries current 3/. The currents flow in the directions shown in Figure 3. Starting with your answer in (a). find the magnetic field (vector) at the centre of the cube (c) What is the magnitude of the force acting on a small current element 1, di = 1, di (1+28) placed at the centre of the cube in (b)