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Difficulty: MediumOhm's Law Calculations and Concepts

An electronics technician tests a DC audio indicator module connected to a 24 V24\text{ V} power supply. An in-line meter measures a steady current flow of 80 mA80\text{ mA} through the component. According to Ohm's law, what is the electrical resistance of the module in ohms (Ω\Omega)?

Answer: 300 Ω

Answer

The total resistance of the module is 300 Ω300\text{ }\Omega.
According to Ohm's law (V=I×RV = I \times R), resistance equals voltage divided by current (R=VIR = \frac{V}{I}). Converting 80 mA80\text{ mA} to standard amperes gives 0.08 A0.08\text{ A}. Dividing the 24 V24\text{ V} source by 0.08 A0.08\text{ A} yields a resistance of 300 Ω300\text{ }\Omega.

Step-by-Step Solution

1
Convert current from milliamperes (mA) to base amperes (A)
80 mA=80×10−3 A=0.08 A80\text{ mA} = 80 \times 10^{-3}\text{ A} = 0.08\text{ A}
Ohm's law requires current to be expressed in standard SI units (amperes) when working with volts and ohms.
2
Rearrange Ohm's law (V=I×RV = I \times R) to isolate resistance (RR)
R=VIR = \frac{V}{I}
Dividing both sides of the standard Ohm's law equation by current isolates the unknown resistance.
3
Substitute the known voltage (24 V24\text{ V}) and current (0.08 A0.08\text{ A}) into the formula
R=24 V0.08 A=300 ΩR = \frac{24\text{ V}}{0.08\text{ A}} = 300\text{ }\Omega
Performing the division calculates the exact resistance value in ohms.

Key Concept

Ohm's law resistance calculation with metric prefix conversion (R=VIR = \frac{V}{I})
Estimated Time:1m 0s
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Ohm's Law Calculations and Concepts

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