A cell having emf $\varepsilon$ and internal resistance r is connected across a variable external resistance R. When the resistance R keeps on increasing the graph of potential difference V across the R will be:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3).
$V=\left(\frac{ε}{R+r}\right)=R=\frac{ε}{1+\frac{R}{r}}$
$∴R=∞,V=ε$