Image text transcribed for accessibility: Suppose the emf of the battery in the circuit shown in the figure below varies with time t so that the current is given by i(t) = 1.50 + 4.50t, where i is in amperes and t is in seconds. Take R = 4.00 Ohm and L = 4.00 H, and find the emf required of the battery at t = 6.00 s.