Primary circuit of potentiometer is shown in figure determine :
(A) current in peimary circuit
(B) potential drop across potentiometer wire AB
( C) potential gradient (means potential drop per unit length of potentiometer wire)
(D) maximum potential which we can measure above potentiometer

Explanation

(a) `i=epsi/(r+R_(1)+R)=2/(1+20+10)rArri=2/31A`
(b) `V_(AB)=iR=2/31xx10rArrV_(AB)=20/31" volt"`
`x=V_(AB)/L=2/31" volt/m"`
(d) Maximum potential which we can measure by it = potential drop across wire `AB=20/31` volt