A point charge +12 μC is located 6 cm vertically above the centre of a square of side 12 cm, as shown. The magnitude of electric flux through the square is N × 10³ N m² C⁻¹. Find N.

Question

G1 Physics · Accepted Answer

Step 1: Reflect the square to form a cube of side 12 cm with the charge at the cube centre (the charge is 6 cm from each face). By symmetry the total flux q/ε₀ divides equally among six faces. Step 2: Φsquare=q/(6ε₀)=12×10⁻⁶/[6(8.85×10⁻¹²)]≈2.26×10⁵ N m² C⁻¹. Step 3: Hence N=226.