Question

Two parallel large thin metal sheets have equal surface charge densities (σ = 26.4 x 10-12 c/m2 ) of opposite signs. the electric field between these sheets is

Answer 1

Electric field intensity between two parallel sheets have equal surface charge densities of opposite sign is given by E = σ/ε₀
Here given, σ = 26.4 × 10⁻¹²C/m²
and ε₀ = 8.875 × 10⁻¹² C²/Nm²

So, Electric field intensity between sheets = 26.4 × 10⁻¹²/8.875 × 10⁻¹² ≈ 3 N/C
Hence, answer is 3N/C

Answer 2

A and B are two parallel plates close to each other. Outer region of plate A is labelled as I, outer region of plate B is labelled as III, and the region between the plates, A and B, is labelled as II.

Charge density of plate A, σ = 17.0 × 10−22 C/m2

Charge density of plate B, σ = −17.0 × 10−22 C/m2

In the regions, I and III, electric field E is zero. This is because charge is not enclosed by the respective plates.

Electric field E in region II is given by the relation,

Where,

∈0 = Permittivity of free space = 8.854 × 10−12 N−1C2 m−2

∴

= 1.92 × 10−10 N/C

Therefore, electric field between the plates is 1.92 × 10−10 N/C.