Question
How many watts are consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance?
Answer Options
- A) Approximately 61 milliwatts
- B) Approximately 61 watts
- C) Approximately 11 milliwatts
- D) Approximately 11 watts
Correct Answer: A
Explanation
To calculate the power (P) consumed, we use the formula P = I^2 R, where I is the current and R is the resistance. First, convert the current from milliamperes (\text{mA}) to amperes (\text{A}): 7.0 \text{ mA} = 0.007 \text{ A}.
Substituting the values, I = 0.007 \text{ A} and R = 1,250 \text{ ohms}: P = I^2 R = (0.007 \text{ A})^2 \times 1250 \text{ }\Omega = 0.000049 \times 1250 = 0.06125 \text{ watts.} Converting back to milliwatts, 0.06125 \text{ watts} is 61.25 \text{ milliwatts}. The power consumed is approximately 61 \text{ milliwatts}.
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