Question

A 2.5g copper penny is given a charge of -4.0*10^-9c. how mny excess electrons are on the penny?

Answer 1

The number of excess electrons on the copper penny is approximately 2.5 x 10^10.

Step-by-step explanation:

To determine the number of excess electrons on the copper penny, we can use the formula:

Number of electrons = Total charge / Charge per electron

Given that the copper penny has a charge of -4.0 x 10^-9 C, the charge per electron is -1.60 x 10^-19 C, since electrons have a negative charge. Plugging in these values, we get:

Number of electrons = (-4.0 x 10^-9 C) / (-1.60 x 10^-19 C) = 2.5 x 10^10 electrons

Therefore, there are approximately 2.5 x 10^10 excess electrons on the penny.

Answer 2

Answer : The excess of electrons on the penny are,
`2.5* 10^(10)` electrons

Solution : Given,

Total charge =
`-4.0* 10^(-9)C`

Charge on electron =
`-1.6* 10^(-19)C`

Formula used :

`\text{Excess of electrons}=\frac{\text{Total charge}}{\text{Charge of electron}}`

Now put all the given values in this formula, we get the excess of electrons present on the penny.

`\text{Excess of electrons}=\frac{\text{Total charge}}{\text{Charge of electron}}=(-4.0* 10^(-9)C)/(-1.6* 10^(-19)C/e^-)=2.5* 10^(10)e^-`

Therefore, the excess of electrons on the penny are,
`2.5* 10^(10)` electrons