Question

Consider a coin of Question 20 . It is electrically neutral and contains equal amounts of positive and negative charge of magnitude 34.8 kC. Suppose that these equal charges were concentrated in two point charges separated by
(i) 1cm `(~(1)/(2)xx`diagonal of the one paisa coin`)`
(ii) 100 m (`~` length of a long building)
(iii) `10^(6)m` (radius of the earth). find the foce on each such point charge in ech of the three cases. what do you conclude from these results?

Answer 1

Here, `q=+-34.8RC=+-3.48xx10^(4)C`
`r_(1)=1cm=10^(-2)m,r_(2)=100m,r_(3)=10^(6)m and (1)/(4piepsi_(0))=9xx10^(9)`
`F_(1)=(|q|^(2))/(4piepsi_(0)r_(1)^(2))=(9xx10^(9)(3.48xx10^(4))^(2))/((10^(-2))^(2))=1.09xx10^(23)N`
`F_(2)=(|q|^(2))/(4piepsi_(0)r_(2)^(2))=(9xx10^(9)(3.48xx10^(4))^(2))/((100)^(2))=1.09xx10^(15)N`
`F_(3)=(|q|^(2))/(4piepsi_(0)r_(3)^(2))=(9xx10^(9)(3.48xx10^(4))^(2))/((10^(6))^(2))=1.09xx10^(7)N`
Conclusion from this result we observe that when `+-` charges in ordinary neutral matter are separated as point charges, they exerted an enormous force. Hence, it is very difficult to distrub electrical neutrality of matter.