Ham Radio Technician Practice Exam 2025 – Comprehensive Prep Resource

To determine the power consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance, we can use the formula for electrical power, which is given by:

\[ P = I^2 \times R \]

Here, \( P \) represents power in watts, \( I \) is the current in amperes, and \( R \) is the resistance in ohms. It's important to convert milliamperes to amperes for this calculation.

1. Convert the current from milliamperes to amperes:

\[

I = 7.0 \text{ mA} = 0.007 \text{ A}

\]

2. Substitute the values into the power formula:

\[

P = (0.007)^2 \times 1250

\]

\[

P = 0.000049 \times 1250

\]

\[

P = 0.06125 \text{ W}

\]

3. Converting watts to milliwatts:

\[

P \approx 61.25 \text{ mW}

\]

This calculation shows that the