A dc power supply has no-load voltage of 30V and a full load voltage of 25 V at a full-load current of 1A. Its output resistance and load regulation, respectively, are

a) 5 ohm and 20%

b) 25 ohm and 20%

c) 5 ohm and 16.7%

d) 25 ohm and 16.7%

Ans (b) 25 ohms and 20%

Load reg = V fl - V _NL/ V _FL  = 30 - 25 /25 = 0.2  i.e 20 %

Resistance = 25 / 1 amp = 25 ohm