An 80 W lamp is connected to the secondary of a step-down transformer, where primary is connected to ac mains of 220 V . Assuming the transformer to be ideal, the current in the primary winding is nearly

Step-by-step solution

In an ideal transformer, input power equals output power. Given the output power P_s = 80 W at the lamp and the primary voltage V_p = 220 V , the primary current I_p satisfies V_p I_p = P_s . Substituting the known values, 220 I_p = 80 , so I_p = 80 220 = 4 11 A 0.3636 A . Rounded to two decimal places, I_p 0.36 A , which corresponds to option C .