At the centre of a half ring of radius R = 10 cm and linear charge density 4 nC m⁻¹, the potential is xπ V. The value of x i s ________.

Question

G1 Physics · Accepted Answer

Potential at the centre due to a ring element: dV = k dq/R Since every element is at the same distance R: V = kQ/R For a half ring: Q = λπR Therefore: V = kλπ Given: k = 9 × 10⁹ λ = 4 × 10⁻⁹ C/m Hence: V = 9 × 10⁹ × 4 × 10⁻⁹ × π = 36π V Therefore: x = 36