Answer Happy

13. Half of a rectangular circuit of resistance R and sides a and 4a is immersed in an external constant magnetic field, as in Figure 7. 4a 2a Fig. 7 The circuit is pulled away from the region of magnetic field with a constant velocity v. (i) Show that the temporal derivative of the flux of the magnetic field is given by: a(B) at -Bav and calculate the current circulating in the circuit. In what direction does the current flow? [7] (ii) Using the result in part (i), calculate the overall force felt by the circuit as it is pulled away. What is the direction of the force for each arm of the circuit? [7] (iii) What is the work done to extract the circuit completely from the magnetic field region? [6]