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Current Electricity — Physics STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity1 Mark
MCQ
In potentiometer experiment, the balancing length is $8 m$ when two cells $E_1$ and $E_2$ are joined in series. When two cells are connected in opposition the balancing length is $4 m$. The ratio of the e.m.f. of the two cells $\left(\frac{E_1}{E_2}\right)$ is
  • A
    $1: 2$
  • B
    $2: 1$
  • C
    $1: 3$
  • ✓
    $3: 1$
✓

Answer

Correct option: D.
$3: 1$
(d) : Given, $E_1+E_2=k \times 8$...(i)
$E_1-E_2=k \times 4$...(ii)
On dividing equation (i) by equation (ii),
$
\begin{aligned}
& \frac{E_1+E_2}{E_1-E_2}=2 \\
& E_1+E_2=2 E_1-2 E_2 ; 3 E_2=E_1 ; E_1: E_2=3: 1
\end{aligned}
$

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