Question

The total number of electrons in the human body is typically in the order of 10²⁸. Suppose, due to some reason, you and your friend lost 1% of this number of electrons. Calculate the electrostatic force between you and your friend separated at a distance of lm. Compare this with your weight. Assume the mass of each person is 60kg and use point charge approximation.

Answer 1

Number of electrons in the human body = 10²⁸

Number of electrons in me and my friend after lost of 1% = 10²⁸ x 1%

`= 10^28 xx 1/100`

n = 10²⁶ electrons

Separation distance d = 1 m

Charge of each person q = 10²⁶ x 1.6 x 10^-19

q = 1.6 x 10⁷ C

Electrostatic force, F = `1/(4 pi epsilon_0) = ("q"_1"q"_2)/"r"^2 = (9 xx 10^9 xx 1.6 xx 10^7 xx 1.6 xx 10^7)/1^2`

F = 2.304 x 10²⁴N

Mass of the person, M = 60 kg

Acceleration due to gravity, g = 9.8 ms^-2

Weight (W) = mg

= 60 x 9.8

W = 588 N

Electrostatic force is equal to 3.92 x 10²¹ times of weight of the person.