Chapter 18, Problem 67GP

(a)

To determine

The power drawn from the source.

Answer to Problem 67GP

  $1462W$

Explanation of Solution

Given:

Power delivered, $P_{delivered}=950W$

Efficiency, $e=65\%$

Formula used:

Formula to calculate the power drawn:

  $P_{source}=\frac{P_{Delivered}}{e}$

Where,

  $P_{Delivered}$ is power delivered.

  $e$ is efficiency.

  $P_{Source}$ is power source.

Calculation:

According to the question, the efficiency of the microwave is $65\%$ . So, the power delivered will be $0.56P_{Source}$ . Now, substitute all the values in the formula:

  $\begin{array}{c}{P}_{Source}=\frac{P_{delivered}}{0.65}\\ =\frac{950}{0.65}\\ =1462W\end{array}$

Conclusion: The required power is $1462W$ .

(b)

To determine

The drawn current.

Answer to Problem 67GP

  $I=12.2A$

Explanation of Solution

Given:

Voltage source, $V_{Source}=120V$

Power source, $P_{Source}=1462W$

Formula used:

  $P=VI$

Where, $P$ is power, $V$ is voltage and $I$ is current.

Calculation:

Rearrange the expression: $P_{Source}=V_{Source}I$

So, $I=\frac{P_{Source}}{V_{Source}}$ .

Substitute all the given values in above equation:

  $I=\frac{1462}{120}=12.2A$

Conclusion: The drawn current is about $12.2A$ .