Question

What is the formula for electrical power in terms of current (I) and resistance (R) of the resistor?

Answer 1

Concept Used: Ohm's law

Step 1: Definition of electrical power

Electrical power is equivalent to the fraction between the square of the voltage (V) and resistance (R). The unit of measurement of electrical power in a standard international system is the watt (W).

Step 2: Formula for electrical power in terms of current (I) and resistance (R)

Write the equation for Ohm's law.

$V=IR$

The relation of electrical power in terms of current and resistance is given by,

$P=\frac{V^2}{R}$

Substitute the equation for the voltage in terms of Ohm's law.

$\begin{array}{rcl}P& =& \frac{{\left(IR\right)}^2}{R}\\ & =& I^{2}R\end{array}$

Here, V is the voltage and R is the resistance.

Thus, the expression for the power in terms of I and R is $\begin{array}{l}{I}^{2}R\end{array}$.