# The current supplied by a battery in a portable device is typically 0.15 A. Find the number of...

## Question:

The current supplied by a battery in a portable device is typically 0.15 A. Find the number of electrons passing through the device in one hour.

## Current:

Current is defined as the quantity of electric charge that is passing through the electric circuit in unit time. A battery is a device that converts chemical energy into electrical energy. The electric charge consists of electrons.

Given data

• Current supplied in battery is: {eq}I = 0.15\;{\rm{A}} {/eq}
• Operation timing is: {eq}t = 1\;{\rm{hour = 3600}}\;{\rm{s}} {/eq}

The expression for the current is given as follows:

{eq}\begin{align*} I &= \dfrac{q}{t}\\ q &= I \times t \end{align*} {/eq}

Where. {eq}q {/eq} is the charge.

Substitute the value in the above expression.

{eq}\begin{align*} q &= 0.15 \times 3600\\ q &= 540\;{\rm{C}}.......(1) \end{align*} {/eq}

The charge of an electron is given as follows:

{eq}\begin{align*} 1\;{\rm{electron}} &= 1.6 \times {10^{ - 19}}\;{\rm{C}}\\ {\rm{1}}\;{\rm{C }}&=\dfrac{1}{{1.6 \times {{10}^{ - 19}}}}\;\;{\rm{electrons}}.......(2) \end{align*} {/eq}

Equate equation (1) and equation (2).

{eq}\begin{align*} q = \dfrac{{540}}{{1.6 \times {{10}^{ - 19}}}}\;\;{\rm{electrons}}\\ q{\rm{ = 337}}{\rm{.5}} \times {\rm{1}}{{\rm{0}}^{19}}\;{\rm{electrons}} \end{align*} {/eq}

Thus, number of electrons passing through the device is {eq}{\rm{337}}{\rm{.5}} \times {\rm{1}}{{\rm{0}}^{19}}\;{\rm{electrons}} {/eq}. 