Chapter 22.1, Problem 6PP

To determine

Electric current through lightbulb.

Answer to Problem 6PP

  $I=0.3\text{A}$

Explanation of Solution

Given:

Power rating of flashlight, $P=0.9\text{W}$

Potential drop across lightbulb, $V=3\text{V}$

Formula Used:

The electrical power is given as,

  $P=VI$

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

Calculation:

On substituting the given values in above relation,

  $\begin{array}{c}0.9=3\times I\\ I=\frac{0.9}{3}\text{A}\\ =0.3\text{A}\end{array}$

Conclusion:

Therefore, the electrical current through lightbulb is $I=0.3\text{A}$ .