According to my book, if we connect a high resistance in series to the secondary cell (whose emf is to be balanced) , connect this whole apparatus to a potentiometer with an auxiliary Emf and find the null point . It's written that even after removing the Hugh resistance the null point comes down to be the same. How's that ? Doesn't the High resistance Infact contribute to increase the effective balancing length? Or do we assume that the potential gradient of the potentiometer far exceeds the potential drop created by the resistance?