Question

What is the number of electric field lines coming out from a 1C charge?

(a) 9*10^9

(b) 8.85*10^-12

(c) \(\frac {1}{8.85}\)*10^-12

(d) Infinite

The question was posed to me in exam.

This intriguing question comes from Gauss’s Law topic in section Charges and Fields of Physics – Class 12

Answer 1

The correct choice is (c) \(\frac {1}{8.85}\)*10^-12

To elaborate: According to Gauss’s Law, the total number of electric field lines coming out of a charge q is = \(\frac {q}{\varepsilon_o}\) where εo is the absolute permittivity of air. Its value is 8.85*10^-12. Therefore the number of lines coming out from a 1C charge = \(\frac {1}{8.85}\)*10^-12.