A ring of charge with radius 0.5 m has 0.002π m gap. If the ring carries a charge of +1 C, the electric field at the centre is
7.5 × 107.NC–1
7.2 × 107.NC–1
6.2 × 107.NC–1
6.5 × 107.NC–1
Q2πr=dqdl dq=Q2πr.dl=12π x 0.5=0.02π1=21000 E=14πε0dqr2⇒9 x 109 x 2 x 10-3122
E = 7.2 × 107 N/C