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Consider a coin Example 20 above. It is electrically neutral and contains equal amounts of positive and negativecharge of magnitude34.8 kC. Supposethat these equalcharges were concentrated in two point chargesseparatedby (i) 1 cm (~1//2 xx diagonal of the one paisa coin), (ii) 100 m (-lengthfo a long building), and (iii) 10^(6) m (radius fo the earth). Find the force on each such pointcharge in each of the three cases. What do youconclude from these results ? |
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Answer» Solution :Here, `q = +- 3.48 KC = +- 3.48xx10^(4) C, r_(1) = 1 cm = 10^(-2) m, r_(2) = 100m , r_(3) = 10^(6) m, F_(1) = ?, F_(2) = ? , F_(3) = ?` According to Coulomb's law, `F_(1) = (|q|^(2))/(4pi in_(0) r_(1)^(2)) = (9XX10^(9)(3.48xx10^(4))^(2))/((10^(-2))^(2)) = 1.09xx10^(23) N`, `F_(2) = (|q|^(2))/(4pi in_(0) r_(2)^(2)) = (9xx10^(9)(3.48xx10^(4))^(2))/((100)^(2)) = 1.09xx10^(15) N`, `F_(3) = (|q|^(2))/(4pi in_(0) r_(3)^(2)) = (9xx10^(9)(3.48xx10^(4))^(2))/((10^(6))^(2)) = 1.09xx10^(7) N` We observe that when`+-` charges in ordinaryneutral matterare separated as point charges, they exert an enomous force. Hence , it is not easy to disturb electrical neutrally of MATTER. |
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