Problem

A $10 \, \mathrm{W}$ resistor has a value of $120 \, \Omega$. What is the rated current through the resistor?

Data

• Power: $P = 10 \, \mathrm{W}$
• Resistance: $R = 120 \, \Omega$

Prerequisite Concept

• Power Formula:
  $P = I^2 R \implies I = \sqrt{\frac{P}{R}}$

Solution

Substitute the values:

$$I = \sqrt{\frac{10}{120}} = \sqrt{0.0833} = 0.2886 \, \mathrm{A}.$$

Answer

• Rated Current: $I = 0.2886 \, \mathrm{A}$

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