A half wave rectifier is used to supply 50V d.c. to a resistance load of `800Omega`. Diode has a resistance of 200Omega. Calculate maximum a.c. voltage required.

A p-n diode is used in a half wave rectifier with a load resistance of 1000 Omega . If the forward resistance (r_(f)) of diode is 10 Omega , calculate the efficiency of this half wave rectifier.