Question

Referring to Figure 21.6, (a) CalculateP₃and note how it compares with${\mathbf{P}}_{\mathbf{3}}$found in the first two example problems in this module. (b) Find the total power supplied by the source and compare it with the sum of the powers dissipated by the resistors.

Short answer

(a)Power in the electrical circuit is$7.16\mathrm{W}$.

(b) Power of the source is $28.22\mathrm{W}$

Step-by-step solution

Definition of current

Electric power is the percentage of time it takes to work or generate energy and is expressed as the work W or the transmitted energy divided by the time interval t.

Calculating P3

(a)

Power in the electrical circuit can be calculated as,

$$\begin{gathered} {\mathrm{P}}_3=\frac{{\mathrm{V}}^2}{{\mathrm{R}}_3} \\ {\mathrm{P}}_3=\frac{{\left(9.65\mathrm{V}\right)}^2}{13\mathrm{\Omega }} \\ {\mathrm{P}}_3=7.16\mathrm{W} \end{gathered}$$

Therefore, the power in the electrical circuit is $7.16\mathrm{W}$.

Finding the total power supplied by source

(b)

Power of the source can be calculated as,

$$\begin{gathered} {\mathrm{P}}_{\mathrm{tot}}={\mathrm{R}}_{\mathrm{tot}}{\overline{)\times }}^2 \\ =\left(5.11\mathrm{\Omega }\right)\times {\left(2.35\mathrm{A}\right)}^2 \\ =28.22\mathrm{W} \end{gathered}$$

When we sum powers dissipated by each resistor, we get to amount of power provided by the source.