Question

Two point charges 20 microcoulomb and 80 microcoulomb are 10 cm apart at which point on the line joining them electric field will be zero

Answer 1

Answer:

The electric field will be zero at 6.67 cm distance from 80 micro coulomb.

Explanation:

Given that,

First charge $q_{1}=20\times10^{-6}$

Second charge $q_{2}=80\times10^{-6}$

Distance$d = 10\ cm$

Let the electric field will be zero at point O.

Two point charges 20 micro coulomb and 80 micro coulomb are 10 cm apart at point A and B.

The distance between O and A is (10-x) cm and the distance between O and B is x cm.

Since,

$E_{A}=E_{B}$

$\dfrac{k\ 20\times10^{-6}}{(10-x)^2}=\dfrac{k\ 80\times10^{-6}}{x^2}$

$20\times10^{-6}\times x^2=(10-x)^2\times80\times10^{-6}$

$x^2=4(10-x)^2$

$x= 6.67 cm$

Hence, The electric field will be zero at 6.67 cm distance from 80 micro coulomb.