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?
0.2 A
0.4 A
2 A
4 A
In an ideal transformer, Input power = Output power. Therefore, V_P I_P = V_S I_S = Given power. 220 * I_P = 44. I_P = 44 / 220 = 0.2 A.
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