question_answer 23)

Figure shows a potentiometer circuit for comparison of two resistances. The balance point with a standard resistor R = 10.0  is found to be 58.3 cm, while that with the unknown resistance X is 68.5 cm. Determine the value of X. What might you do if you failed to find a balance point with the given cell of emf ?  

Answer:

(a)                                                                (b) To obtain balance point, either a cell of less e.m.f. be used or a suitable resistor be put in series with R and so that potential drop across the wire AB is reduced.