Ideal transformer conserves power: P_primary = P_secondary Steps:

• Secondary current I_s = V_s / R = 240 V / 120 Ω = 2 A
• Power dissipated P = V_s × I_s = 240 V × 2 A = 480 W
• Primary power = 480 W (100% efficiency)
• Primary current I_p = P / V_p = 480 W / 600 V = 0.8 A Why C is correct:
• Matches 480 W from V_s²/R and 0.8 A from P/V_p, per power conservation in ideal transformers Why the others are wrong:
• A: Assumes wrong V_s = 120 V, yielding P = 120 W and I_p = 0.2 A
• B: Wrong P = 420 W (miscalculation of V_s²/R), with inconsistent I_p = 0.5 A (should be 0.7 A)
• D: Correct P but wrong I_p = 1.3 A (misapplies turns ratio V_p/V_s instead of I_s × V_s/V_p) Final answer: C