Two charges are separated as shown in diagram A. Each charge has magnitude 50 nC. In diagram B, the charge on the right is moved farther to the right. To keep the electric-field magnitude at the centre equal to its original value, an additional charge α/9 nC must be removed from the left charge. Find α.

Question

G1 Physics · Accepted Answer

Step 1: Use superposition, 𝐄 = Σ[1/(4πε₀)] qᵢ 𝐫ᵢ/rᵢ³, or the appropriate continuous-distribution integral. Step 2: Resolve components and exploit symmetry to cancel components. Step 3: Add the surviving components and compare with the choices. Final: 400.