Prefix conversion: A half-watt is equal to how many milliwatts (mW)?
Electrical Engineering
Energy and Power
Difficulty: Easy
Choose an option
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A5,000 mW
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B5 mW
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C500 mW
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D50 mW
Answer
Correct Answer: 500 mW
Explanation
Introduction / Context:Quickly converting between watts and milliwatts is essential when matching component power ratings and interpreting datasheets. This problem checks familiarity with the 10^3 relationship between W and mW.
Given Data / Assumptions:
- Half-watt = 0.5 W.
- 1 W = 1,000 mW.
Concept / Approach:To convert watts to milliwatts, multiply by 1,000. Apply this directly to 0.5 W to get the value in mW.
Step-by-Step Solution:
Start with 0.5 W.Multiply by 1,000: 0.5 * 1,000 = 500.Therefore, 0.5 W = 500 mW.Verification / Alternative check:Reverse: 500 mW / 1,000 = 0.5 W, confirming the conversion is correct.
Why Other Options Are Wrong:
- 5,000 mW: Equals 5 W, not 0.5 W.
- 5 mW: Equals 0.005 W, too small by a factor of 100.
- 50 mW: Equals 0.05 W, too small by a factor of 10.
Common Pitfalls:
- Misplacing the decimal during scaling by 1,000.
Final Answer:500 mW