Answer:
E = -1.5 10⁵ N / C
Step-by-step explanation:
In a capacitor the electric field is uniform between the blades, therefore we use the expression
V = - E s
E = - V / s
let's calculate
E = - 3000 / 0.02
E = -1.5 10⁵ N / C
the sign indicates that the field and the potential are opposite, when one increases the gold decreases