Question

$n$ identical cells each $emf$ $\left(E\right)$ and internal resistance $\left(r\right)$ are joined in series so as to form a closed circuit. The potential difference across any one cell is :

• A. zero
• B. $\epsilon$
• C. $\epsilon /n$
• D. $\frac{n-1}{n}\epsilon$

Answer 1

Answer: (A)

zero

Let the current in the circuit be $i$,

$E-ir+E-ir+E-ir+E-ir..............ntimes=0$

$n(E-ir)=0$

$i=\frac{E}{r}$

Now consider a cell with $emf,E$ and internal resistance $r$,

$V_A+E-ir=V_B$

$V_A-V_B=\Delta V=E-ir=0$

Option $\text{A}$ is the correct answer.