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Question 4 (7 marks) Suppose a current loop consists of a fixed "U" shape and a moveable conducting bar connecting the ends of the "U" as below: 1 The radius of the rounded part is 3 cm. The U is made of wire and has negligible resistance while the resistance of the bar is 6 Ohms. a) If the entire Ushape is in a region with uniform magnetic field of 4 Tout of the page, what is the current (magnitude and direction) that flows if the rod is dragged to the right at 5 m/s? (3 marks) b) What force is required to keep the bar moving at a steady pace? (1 mark)

c) If the rod becomes stuck, how quickly does the magentic field need to change (in T/s) to maintain the same current? Should the field strength increase or decrease? (3 marks)