A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V, 44 W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit ? (1) 4 A (2) 0.2 A (3) 0.4 A (4) 2 A
Vp=220V Vs=11V P=44W As it is an ideal transformer VPiP=VSiS=44W 220×iP=44 iP=22044=51=0.2A
