See this in the second part to find length 'l' ...v consider the sec circuit.there y r is 0.3 not 0.3+1.2 .PL ansto the point.

See this in the second part to find length 'l' ...v consider the sec circuit.there y r is 0.3 not 0.3+1.2 .PL ansto the point. (ii) In the following potentiometer circuit AB is a uniform wire of length I m and resistance the potential gradient along the wire and balance length AO I 0.3