Two charges of `+25xx10^(-9)C` and `-25xx10^(-9)C` are placed 6 m apart. Find an electric field at a point 4 m from the centre of the electric dipole (i) on axial line (ii) on equatorial line.

Explanation

Here, `q=25xx10^(-9)C,2a=6m,r=4m`
`p=q(2a)=25xx10^(-9)xx6`
`=1.5xx10^(-7)"C-m"`
Now, `E_("axial")=(1)/(4piepsilon_(0))*(2pr)/((r^(2)-a^(2))^(2))`
`=(9xx10^(9)xx2xx1.5xx10^(-7)xx4)/((4^(4)-3^(2))^(2))=(2700xx4)/(49)`
`E_("axial")=220.4"NC"^(-1)`
`E_("equatorial")=(1)/(4piepsilon_(0))*(p)/((r^(2)+a^(2))^(3//2))`
`=(9xx10^(9)xx1.5xx10^(-7))/((4^(2)+3^(2))^(3//2))=(1350)/(125)=10.8" N C"^(-1)`