AB is a potentiometer wire. If the value of R is increased, in which direction will the balance point J shift?
AB is a potentiometer wire. If the value of R is increased, in which direction will the balance point J shift?

The potential difference across AB dropped as the value of grew, and therefore the potential gradient across AB decreased. 
E’ kl is the formula for this.
When the balance length increases, the jockey shifts towards B.