Answer: σ = 2.47 × 10^-8 q/m²
Explanation: The electric field intensity and surface charge density for an infinite sheet is given as
E =σ/2ε₀
Where E = 1.4KN/c = 1400 N/c
ε₀ = permittivity of free space = 8.85×10^-12
σ = surface charge density
1400 = σ/2×8.85×10^-12
σ = 1400 × 2 × 8.85×10^-12
σ = 24780×10^-12
σ = 2.47 × 10^-8 q/m²