Chapter 9, Problem 9.1CYU

Check Your Understanding Handheld calculators often use small solar cells to supply the energy required to complete the calculations needed to complete your next physics exam. The current needed to run your calculator can be as small as 0.30 mA. How long would it take for 1.00 C of charge to flow from the solar cells? Can solar cells be used, instead of batteries, to stall traditional internal combustion engines presently used in most cars and trucks?

To determine

The time taken for the $1.00\text{C}$ of charge to flow from the solar cells and whether the solar cells can be used to start the traditional internal combustion engines or not.

Answer to Problem 9.1CYU

The time taken for the $1.00\text{C}$ of charge to flow from the solar cells are $3333.33\text{s}$ and the solar cells cannot be used to start the traditional internal combustion engines.

Explanation of Solution

Given:

The charge in the solar cell is $\Delta Q=1.00\text{C}$.

The current is $I=0.30\text{mA}$.

Formula used:

The flow of the current is given by,

  $\begin{array}{l}I=\frac{\Delta Q}{\Delta t}\\ \Delta t=\frac{\Delta Q}{I}\end{array}$

Calculation:

The flow of the current is calculated as,

  $\begin{array}{c}\Delta t=\frac{\Delta Q}{I}\\ =\frac{1.00\text{C}}{0.30\text{mA}\left(\frac{1\text{A}}{{10}^3\text{mA}}\right)}\\ =3333.33\text{C}/\text{A}\left(\frac{\text{A}}{\text{C}/\text{s}}\right)\\ =3333.33\text{s}\end{array}$

The stator of the traditional internal combustion engine required the large amount of current in a very short period of time. But the solar cells provide small amount of current for the large period of the time. Therefore, the solar cells are not used to starts the traditional internal combustion engines.

Conclusion:

The time taken for the $1.00\text{C}$ of charge to flow from the solar cells are $3333.33\text{s}$ and the solar cells cannot be used to start the traditional internal combustion engines.