Consider a coin of example 1.20. 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 a) 1 cm b) 100 m Find the force on each such point charge in each of the three cases. What do you conclude from these results?
(i)F=14πε0q2r2=9×109×(3.48×104)2(10−2)2F=14πε0q2r2=9×109×(3.48×104)2(10-2)2 =1.1×1023=1.1×1023 N (ii)F=14πε0q2r2=9×109×(3.48×104)2(102)2F=14πε0q2r2=9×109×(3.48×104)2(102)2 =1.1×1015=1.1×1015 N (iii) F=14πε0q2r2=9×109×(3.48×104)2(106)2F=14πε0q2r2=9×109×(3.48×104)2(106)2 =1.1×107=1.1×107 N
