Question

Common static electricity involves charges ranging from nanocoulombs to microcoulombs. (a) How many electrons are needed to form a charge of −7.50 nC? electrons (b) How many electrons must be removed from a neutral object to leave a net charge of 0.580 µC? electrons

Answer 1

a) 4.681*10^10 electrons

b) 3.67*10^12 electrons

Step-by-step explanation:

The amount of electrons in a charge of 1C is:

`1C=6.2415*10^(18)\ electrons`

You use the previous equality as a conversion factor.

a) The sing of the charge is not important in the calculation of the number electrons, so, you use the absolute value of the charge

`7.50nC=7.50*10^(-9)C*(6.2415*10^(18))/(1C)=4.681*10^(10)\ electrons`

In 7.50nC there are 4.61*10^18 electrons

b)

`0.580\mu C=0.580*10^(-6)C*(6.2415*10^(18))/(1C)=3.67*10^(12)\ electrons`

To obtain a charge of 0.580 µC in a neutral object you need to take out 3.67*10^12 electrons