Two small iron particles, each of mass 280 mg, are. placed at a distance 10 cm apart. If 0.01% of the electron. of one particle are transferred to the other, find the. electric force between them. Atomic weifht of iron is `56 g mol^(-)` and there are 26 electrons in each atom of iron.

Explanation

The atoic weight of iron is`56g mol^(-1).` Thus,
56 g of iron contains `6 xx 10 ^(23)` atoms and each atom contains 26 electrons. Hence, 280 mg of iron contains
`(280 mg xx 6xx 10^23xx26)/(56g) = 7.8 xx 10^(22)` electron
. The number of electrons transferred from one particle
to another
`= (0.01)/(100) xx 7.8 xx 10^18.` The charge transferred is, therefore,
`1.6xx 10 ^(-19) C xx 7.8 xx 10 ^18 =1.2 C`
The electric force between the particles is
`(9xx 10 ^9 Nm^2 C^(-2)) (1.2C^2 )/(10xx10^(-2)m^2)`
`= 1.3 xx 10 ^(12)` N
. This equals the load of apporximately 2000 million
grown- up persons!