Question

an electron is positioned in a uniform electric field. the force on the electron due to the electric field is equal to the force of gravity on the electron. what is the magnitude of this electric field?

Answer 1

Given:

An electron is placed in a uniform electric field such that the electrostatic force on the electron is equal to the gravitational force on the electron.

To find:

Magnitude of Electrostatic Field.

Calculation:

The electrostatic force on the electron mass be equal and opposite to the gravitational force in order to to produce translational equilibrium for the electron.

• Since gravitational force acts on the electron in a downward direction, the electrostatic force has to act in upward direction to nullify it.

$\therefore \: F_{(gravity)} = F_{(electrostatic)}$

$= > \: mg = qE$

$= > \: E = \dfrac{mg}{q}$

So, the final answer is:

$\boxed{\: {\boxed{ \bold{E = \dfrac{mg}{q} }}} \: \: \rm{ in \: upward \: direction}}$