An avionics technician is troubleshooting a direct-current (DC) audio preamplifier circuit… — Armed Services Vocational Aptitude Battery (ASVAB)

An avionics technician is troubleshooting a direct-current (DC) audio preamplifier circuit. The circuit is powered by an $18\text{ V}$ DC source and draws a steady current of $2.5\text{ mA}$ . What is the total resistance of the circuit in kilohms ( $\text{k}\Omega$ )?

Answer: 7.2 kΩ

Answer

7.2 kΩ

According to Ohm's Law, resistance is determined by dividing voltage by current (

R = \frac{V}{I}

). Converting

2.5\text{ mA}

0.0025\text{ A}

and dividing

18\text{ V}

0.0025\text{ A}

yields

7200\ \Omega

, which equals

7.2\text{ k}\Omega

Step-by-Step Solution

Convert the current measurement from milliamperes (mA) to base amperes (A)

I = 2.5\text{ mA} = 0.0025\text{ A}

Ohm's Law formulas require electrical quantities to be in standard base units (volts, amperes, and ohms) before computation.

Apply Ohm's Law rearranged to solve for resistance (

R = \frac{V}{I}

)

R = \frac{18\text{ V}}{0.0025\text{ A}} = 7200\ \Omega

Resistance equals the electromotive force divided by the resulting current flow.

Convert the calculated resistance from ohms (Ω) to kilohms (kΩ)

R = \frac{7200\ \Omega}{1000\ \Omega/\text{k}\Omega} = 7.2\text{ k}\Omega

The question specifically requests the final numerical value in kilohms.

Key Concept

Ohm's Law (

R = \frac{V}{I}

) with metric prefix conversion (

1\text{ mA} = 10^{-3}\text{ A}

and

1\text{ k}\Omega = 10^{3}\ \Omega

)

Estimated Time:45s

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