Question

Two point charges + 2 into minus q are fixed on x-axis at position a into a from origin respectively at what position on the axis resultant electric field is zero

Answer 1

Answer:let the electric field be zero at a position x from the origin

1= particle +q

2=particle -2q

we know that electric field can be zero only at one place ie on the left of particle +q

E1=kq/(a-x)²

E2=k(-2q)/(2a-x)²

E1+E2=0

E1=-E2

kq/(a-x)²=2qk/(2a-x)²

1/a-x=√2/(2a-x)

2a-x=√2(a-x)

2a-√2a=-√2x+x

√2a(√2-1)=-x(√2-1)

x=-√2a

therefore its at a distance of √2a on the left side of number line.

:)