question_answer

A potentiometer circuit is set up as shown. The potential gradient across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0 A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at lengths \[{{\text{l}}_{\text{1}}}\text{cm}\] and \[{{\text{l}}_{2}}\text{cm}\] respectively. The magnitudes, of the resistors R and X, in ohm, are then, equal, respectively, to

A) \[\text{k(}{{\text{l}}_{\text{2}}}-{{\text{l}}_{\text{1}}}\text{)}\,\text{and}\,\text{k}{{\text{l}}_{\text{2}}}\]               

B) \[\text{k}{{\text{l}}_{\text{2}}}\,\text{and}\,\text{k}\,\text{(}{{\text{l}}_{\text{2}}}-{{\text{l}}_{\text{1}}})\]

C) \[\text{k(}{{\text{l}}_{\text{2}}}-{{\text{l}}_{\text{1}}})\,\,\text{and}\,\text{k}\,{{\text{l}}_{\text{1}}}\]               

D) \[\text{k}{{\text{l}}_{\text{2}}}\,\text{and}\,\text{k}{{\text{l}}_{2}}\]