The electric field intensity at the mid point of a dipole with charge ±q and dipole length 2a is:

$\frac{1}{4πε_0}\frac{2q}{a^2}$

The correct answer is Option (1) → $\frac{1}{4πε_0}\frac{2q}{a^2}$

Electric field due to dipole is -

$E=\frac{1}{4πε_0}\frac{2p}{r^3}$

Now, $\vec p=q.2a$   [p = dipole moment]

$∴E=\frac{1}{4πε_0}\frac{q.2a}{a^2}=\frac{1}{4πε_0}\frac{2q}{a}$