Read the passage and answer the question(s).

The potential at any point P of a static electric field is defined as the work done by an external agent in slowly bringing a unit positive charge from infinity to that point. Figure shows potential variation along the line of charges. Two point charges Q₁ and Q₂ lie along a line at some distance from each other. 

At which of the points, 1 ,2 and 3 is the electric field zero?

3

At Point 3 Electric potential is maximum hence Slope of the curve is zero at 3 and E = -dV/dr =   0.