Engineering
Physics
Basic Circuit Theory and Kirchoffs Law for DC Circuit
RC Circuit
Magnetic Field
Question
A cell of emf 'E' and internal resistance r is connected across a variable resistor 'R'. Plot a graph showing variation of terminal voltage 'V' of the cell versus the current 'I'. Using the plot, show how the emf of the cell and its internal resistance can be determined.
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Solution
Given : A cell of emf 'E' and internal resistance r is connected across a variable resistor 'R'.
To find : Plot a graph showing variation of terminal voltage 'V' of the cell versus the current 'I'. Using the plot, show how the emf of the cell and its internal resistance can be determined.
The relation between V and I is given by :
V = E – Ir
Thus the graph between I and V is ass shown in fig(i).
Emf is given by the intercept on the vertical axis, i.e., the V-axis.
Internal resistance is given by the slope of the line i.e., slope of V vs I graph.
