A student measures the terminal potential difference \( V \) of a cell of emf \( \varepsilon \) and internal resistance \( r \) as a function of the current \( I \) flowing through it. Which of the following graphs will give the values of emf \( \varepsilon \) and internal resistance \( r \)?
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Always remember: \(V = \varepsilon - Ir\) gives a straight line with negative slope. Intercept = emf and slope = internal resistance.
