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Question 1 A uniform bar of length L carries a current in the direction from point a to point b. The bar is in a uniform magnetic field that is directed into the page. Consider the torque about an axis perpendicular to the bar at point a that is due to the force that the magnetic field exerts on the bar. (a) Suppose that an infinitesimal section of the bar has length dx and is located a distance x from point a. Calculate the torque du about point a due to the magnetic force on this infinitesimal section. (b)Use u=1dt to calculate the total torque t on the bar, (c) Show that t is the same as though all of the magnetic force acted at the midpoint of the bar. Вх хь dx Question 2 A coil consisting of 50 circular loops with radius 0.50 m carries a 4.0-A current. (a) Find the magnetic field at a point along the axis of the coil, 0.70 m from the center. (b) Along the axis, at what distance from the center of the coil is the field magnitude as great as it is at the center?