Key Idea: It is given that the ring is conducting. As the ring is conducting, so electric field at its centre is zero, ie, Etotal =0 EAKB+EACDBEACDBEACDB=0=−EAKB=−E (along KO ) Therefore, the electric field at the centre due to the charge on the part ACDB of the ring is E along OK. lternative :
The fields at O due to AC and BD cancel each other. The field due to CD is acting in the direction OK and equal in magnitude to E due to AKB.