Question

Question is here

=> point charge of 9 micro coloumb and -6 micro coloumb are placed 90 cm apart . How many points can you find on the line where electrical potential is 0 ?

=> At what distance these points are located from 9 micro cooling charge ?​

Answer 1

Let x cm from charge 9 micro coulomb we get electrical potential equal to zero.

$9\mu C$.....x.....P......(90-x)......$-6\mu C$

we know formula of electrical potential is given by, $V=\frac{Kq}{r}$

so, potential due to charge $9\mu C$ + potential due to charge $-6\mu C$ = 0

or, k($9\mu C$)/x + k($-6\mu C$)/(90 - x) = 0

or, 9/x - 6/(90 - x) = 0

or, 9/x = 6/(90 - x)

or, 3(90 - x) = 2x

or, 270 - 3x = 2x

or, x = 54cm

hence, there is only one point where we get electrical potential=0.

and 54cm from $9\mu C$ charge, electrical potential will be zero.