Apply Ohm’s law: when 12 mA flows through a 1.2 kΩ resistor, determine the voltage drop across the resistor (express in volts).

Difficulty: Easy

Correct Answer: 14.4 V

Explanation:


Introduction / Context:
Voltage across a resistor is the product of current and resistance. This direct application of Ohm’s law appears constantly in biasing networks and sensor readouts, where small currents through kilo-ohm resistors create measurable voltages.


Given Data / Assumptions:

  • I = 12 mA = 0.012 A.
  • R = 1.2 kΩ = 1,200 Ω.
  • Use V = I * R.


Concept / Approach:

Convert units carefully to maintain consistency, then multiply. Since both values are exact in this context, no rounding beyond standard decimal arithmetic is required.


Step-by-Step Solution:

Convert current: 12 mA = 0.012 A.Convert resistance: 1.2 kΩ = 1,200 Ω.Compute voltage: V = I * R = 0.012 * 1,200 = 14.4 V.


Verification / Alternative check:

Using prefixes directly: 12 mA * 1.2 kΩ = (12 × 10^-3) * (1.2 × 10^3) = 14.4 × 10^0 = 14.4 V.


Why Other Options Are Wrong:

1.4 V and 10 V do not satisfy V = I * R with the given values; 100 V is far too large for milliampere currents through kilo-ohm resistances.


Common Pitfalls:

Mixing milli and kilo prefixes; dropping a power of ten; forgetting that volts scale linearly with both I and R.


Final Answer:

14.4 V

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