A 0.250-H inductor carries a time-varying current given by the expression i = (l24 mA) cos [(240

Question:

A 0.250-H inductor carries a time-varying current given by the expression i = (l24 mA) cos [(240 π/s) t].
(a) Find an expression for the induced emf as a function of time. Graph the current and induced emf as functions of time for t = 0 to t = 1/60s.
(b) What is the maximum emf? What is the current wben the induced emf is a maximum?
(c) What is the maximum current? What is the induced emf when the current is a maximum?