When a cell of e.m.f 3.06V is connected, the balance of a potentiometer is 75cm, Calculate the new balance of a cell of e.m.f 2.295V
A
56.26cm
B
73.20cm
C
77.80cm
D
78.70cm
Verified Correct Answer: A.
Physical Principles & Numerical Solution
The balance length of a potentiometer is directly proportional to the e.m.f
Thus, \(\frac{L_1}{L_2} = \frac{E_1}{E_2}\)
\(L_2 = L_1\times \frac{E_2}{E_1}\)
\(L_2 = 75 \times \frac{2.295}{3.06}\)
= 75 x 0.750 = 56.25cm
Source: WAEC / JAMB / NECO Classroom Archive (Record #70475)