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Electric Charges And Fields

Question
CBSEENPH12037146

Check that the ratio ke2Gmempis dimensionless. Look up a table of physical constants and determine the value of this ratio. What does the ratio signify?

Solution

                       Electrostatic force is given by F = Kq1q2r2Gravitational force is given by F =Gm1m2r2
                      where G = 6.67 × 10-11N m2 kg-2            me = 9.1 × 10-31 kg             m p = 1.67 × 10-27 kg            e = 1.6 × 10-19 C
and   k=14πε0 = 9×109 Nm2C2
Now,       ke2Gmemp = 9×109Nm2C2×1.6×10-19C×1.6×10-19C6.67×10-11Nm2kg-2×9.1×10-31kg×1.67×10-27kg                 = 2 × 27 × 1039 which is dimensionless.

It also establishes that the electrostatic force is about 10
39 times stronger than the gravitational force.