SK0-004 · Question #660
An 800W power supply running full load at 220VAC (single phase) draws approximately:
The correct answer is C. 3.64A. Applying the formula I = P / V to an 800W load at 220VAC yields approximately 3.64 amperes.
Question
An 800W power supply running full load at 220VAC (single phase) draws approximately:
Options
- A0.275A
- B1.76A
- C3.64A
- D6.67A
How the community answered
(34 responses)- A18% (6)
- B3% (1)
- C71% (24)
- D9% (3)
Why each option
Applying the formula I = P / V to an 800W load at 220VAC yields approximately 3.64 amperes.
0.275A would require a supply voltage of roughly 2,909V, which is not a standard distribution voltage and bears no relation to the 220VAC specified.
1.76A corresponds to 800W at approximately 454V, not 220VAC, indicating an incorrect voltage value was used in the calculation.
Current equals power divided by voltage: 800W / 220V = 3.636A, which rounds to 3.64A. This is the direct application of the single-phase AC power relationship I = P / V, and the result is only correct when the given supply voltage of 220VAC is used as the divisor.
6.67A is the correct result for 800W at 120VAC (800 / 120 = 6.67), not 220VAC - this answer confuses the two common supply voltages.
Concept tested: Single-phase AC current calculation using I = P / V
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