Answer:
6.20×10⁴ V/m
Step-by-step explanation:
The magnitude of electric field is:
E = √(Eₓ² + Eᵧ²)
where Eₓ = ∂φ/∂x and Eᵧ = ∂φ/∂y.
φ = 1.11 (x² + y²)^-½ − 429x
Eₓ = -0.555 (x² + y²)^-(³/₂) (2x) − 429
Eᵧ = -0.555 (x² + y²)^-(³/₂) (2y)
Evaluating at (0.003, 0.003):
Eₓ = -44034 V/m
Eᵧ = -43605 V/m
The magnitude is:
E = 61971 V/m
Rounded to three significant figures, the strength of the electric field is 6.20×10⁴ V/m.