The student sets up an experiment in the lab to determine the internal resistance of a cell by the…
Physics20251 markShort answer
The student sets up an experiment in the lab to determine the internal resistance of a cell by the graphical method. The circuit is set up as shown, using a cell of e.m.f. $E$ and internal resistance $r$, a variable resistor $R$ and a milliammeter. A voltmeter $V$ is connected to the circuit as shown.
Draw the nature of the graph so determined. What does the Y-intercept of the graph represent?
Figure 59
Answer
Answer
Official answer key
Graph: terminal voltage V (y-axis, volt) against current I (x-axis, ampere) is a straight line sloping downwards from the y-axis.
Y-intercept gives the emf of the cell.
Check your working with the Circuit solver (Kirchhoff's laws): every current, p.d. and power in a circuit of cells and resistors; equivalent resistance too.
Check your working with the Physics formula calculator: about 145 ISC Physics formulas: fill in what you know, with units, and get the rest.
