Question 1 A galvanometer (pictured below) works much like a dc motor, but is used to measure electric current. It produces an angular deflection that depends on the current passing through a coil. 0 N S Like a dc motor, its torque is proportional to current (r, = at) and the back emf is related to the angular velocity (em = a) where a represents the torque and back emf constant. The only real difference between a galvanometer and dc motor is that the motor shaft is attached to a spring. The electrical circuit and rotating mechanism of the galvanometer can be represented by: R L 000 Coil K + e(t) D em B -- J Find the two equations that describe the motion of the electromechanical system. di dt eRi+L+ 0 J + BO+ KO = 0 di e=Ri+L+ a0 dt J + BO+KO = ai di eRi+L+ ab dt J + BO = ai e = Ri + ab j+BO+KO ai