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A
0.5 A
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B
1 A
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C
120 A
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D
2 A
Why this is the answer
Each bulb individually: P = VI, so I = P/V = 60/120 = 0.5 A. In parallel, currents add: total I = 0.5 + 0.5 = 1 A. Verify: total power = 60 + 60 = 120W; P = VI = 120 × 1 = 120W ✓. Parallel circuit principles: (1) SAME VOLTAGE across all branches (each bulb gets full 120V); (2) CURRENTS ADD (total = sum of branch currents); (3) Each branch operates independently — turning one off doesn't affect the other. If the same two bulbs were in SERIES: each would get half the voltage (60V), so each would operate at 1/4 normal brightness (power = V²/R, so half voltage means 1/4 power). Both bulbs would draw the same current. Calculation: each bulb's resistance = V²/P = 120²/60 = 240Ω. In series, total R = 240 + 240 = 480Ω. Current = V/R = 120/480 = 0.25 A. Power dissipated = I²R = 0.0625 × 480 = 30W total (15W per bulb) — far dimmer than rated. This is why household appliances are wired in parallel, not series — each gets full voltage and full power regardless of others. Christmas lights: old-style series-wired light strings each bulb gets a fraction of line voltage (120V/50 bulbs = 2.4V per bulb); when one bulb burns out, the entire string goes out. Modern strings either use parallel wiring or have shunt mechanisms in each bulb that bypass burned-out filaments. LED Christmas lights use LEDs with appropriate series resistors and circuit design. ASVAB EI calculations: practice converting between V, I, R, P using Ohm's Law and Power Law, and applying series/parallel rules. Watts, volts, amps, and ohms are the four fundamental electrical quantities — knowing any two often lets you calculate the others.
Source: ASVAB EI, Parallel Circuit Calculations