A cell of emf E is connected across a resistance R. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be

Question

A cell of emf E is connected across a resistance R. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be (A) R[(E/V)-1] (B) R[(E/V)+1] (C) E R (D) (E-V) R

Tardigrade Admin · Accepted Answer

Internal resistance (r) is given by r=(E-V/i) Also, i=(V/R), we have r=(E-V/V / R) ⇒ r=R((E/V)-1)

Q. A cell of emf $E$ is connected across a resistance $R$ . The potential difference between the terminals of the cell is found to be $V$ . The internal resistance of the cell must be

$R [\frac{E}{V} - 1]$

$R [\frac{E}{V} + 1]$

$ER$

$(E - V) R$

Internal resistance (r) is given by
$r = \frac{E - V}{i}$
Also, $i = \frac{V}{R}$ , we have
$r = \frac{E - V}{V / R}$
$\Rightarrow r = R (\frac{E}{V} - 1)$

Q. A cell of emf E is connected across a resistance R. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be

R[VE​−1]

R[VE​+1]

ER

(E−V)R