Question

a copper coin has a positive charge of 1.37 into 10 raise to 5 C .if the negative charge of the same value is on another coin and the distance between the two is 100m , find the coulomb force between the two.​

Answer 1

Given mass of copper penny =2.35g

Atomic mass of copper =63.5g

Avogadro number =6.02×10

23

Atomic number of copper =29

We have to find the positive or negative charges on 2.35 of copper.

First, we find the total number of atoms in 2.35g of copper.

=

63.5

2.35

×6.02×10

23

=0.22×10

23

atoms

Since one atom of copper contains 29 electrons (and 29 protons).

So, 0.22×10

23

atoms contain =29×0.22×10

23

electrons or protons.

So total positive/negative charges in 2.35g of copper is =29×0.22×10

23

×1.6×10

−19

C

=10.208×10

4

C

and equal amount of negative charge (−10.208×10

4

C)

where 1.6×10

−19

is charge on proton/electron.