a) Explain the applications of PN junction diode. (6) b) A full-wave, 1 -phase rectifier employs a double diode valve, the internal resistance of each element of which may be assumed constant at 500Ω. The transformer r. m. s. secondary voltage from the centre-tap to each anode is 300 V and the load has a resistance of 2000Ω Evaluate:- (10) (i) means load current. (ii) r.m.s. value of load current (iii) the d.c. output power (iv) the input power to the anode circuit (v) the rectification efficiency