plz explain its answer In the potentiometer arrangement

Last updated: 6/14/2023

plz explain its answer In the potentiometer arrangement shown the driving cell D has emf E and internal resistance r The cell C whose emf is to be measured has emfE 2 and internal resistance 2r The potentiometer wire is 100 cm long If balance is obtained the length AJ 1 A This question has multiple correct options B C 1 50cm 1 D e r I 50 cm C 8 2r balance will be obtained only if resistance of AB is r J B