Experiment E2 Flashcards
Does it matter in what order the components are connected? Explain.
No, it does not matter because it is a simple series circuit, thus the current at all points on the circuit should be the same.
In this experiment, I is the dependent and R is the independent variable. Is this correct? Explain.
Yes, it is. A variable resistor is used, thus resistance can be changed, making (R) the independent variable. Current is the variable being measured, thus making current (I) the dependant variable.
Write down the equation for E in terms of the current, I, the external resistance, R, and the internal
resistance of the cell, r.
E = I(R+r)
Show that equation (E2.1) can be rearranged into a form suitable for plotting a straight-
line graph: 1/I = 1/E (R) + r/E
Explain what should be plotted against what in order to get a straight-line graph, and what you can determine from the slope and the intercepts on both axes.
The value of 1/I should be plotted on the y-axis while the value of R should be plotted on the x-axis. The y-intercept gives the value of r/E and the x-intercept gives you the value of -r, which thus allows the internal resistance of the battery to be obtained. The gradient of the graph gives the value of 1/E from which the emf of the battery can be calculated.
Is it necessary to show the origin on the graph if both intercepts are to be read off? Explain.
Yes, because the graph needs to extrapolated to obtain values for the intercepts, i.e. R=0 and 1/I=0
