Point A lies at a distance r on the axis of q short electric dipole. Electric field at this point is $160 \frac{V}{m}$. Now consider another point P at a distance 2r on its axis. The value of electric field at this point will be

$20 \frac{V}{m}$

The correct answer is Option (3) → $20 \frac{V}{m}$

Electric field due to a dipole on its axis.

$E=\frac{2 K P}{r^3} ; E \propto \frac{1}{r^3}$

$\frac{E_1}{E_2}=\left(\frac{r_2}{r_1}\right)^3$

$\frac{160}{E_2}=\left(\frac{2 r}{r}\right)^3$

$E_2=\frac{160}{8}=20 \frac{V}{m}$