Question

An electron is a negatively charged particle that has a charge of magnitude, e - 1.60 x 10-19 C. Which one of the following statements best describes the electric field at a distance r from the electron? The electric field is directed toward the electron and has a magnitude of ke/r. The electric field is directed away from the electron and has a magnitude of ke/2. The electric field is directed toward the electron and has a magnitude of ke/? The electric field is directed toward the electron and has a magnitude of ke?/r. The electric field is directed away from the electron and has a magnitude of ke/r.

Answer 1

Explanation:

The charge on the electron is, $q=-1.6\times 10^{-19}\ C$

The electric field at a distance r from the electron is :

$E=k\dfrac{q}{r^2}$

Where

k is the electrostatic constant, $k=\dfrac{1}{4\pi \epsilon_o}$

We know that the electric field lines starts from positive charge and ends at the negative charge. Also, for a positive charge the field lines are outwards while for a negative charge the field lines are inwards.

So, the correct option is " the  electric field is directed toward the electron and has a magnitude of $k\dfrac{q}{r^2}$. Hence, this is the required solution.