e.m.f. and Internal Resistance Lab

KSSM Physics Form 5, Chapter 3 Electricity. Aim: determine the e.m.f., E, and the internal resistance, r, of a dry cell by plotting a graph of V against I, using V = E − Ir.

1Connect the apparatus

Drag any apparatus to move it. Click one terminal, then a second terminal, to join them with a wire. Click a wire to remove it. Diagrams match a typical school lab schematic.

Rheostat slider Dry cells

Set the current to

2Record readings

Slide the rheostat, then record the ammeter and voltmeter readings. The table of I and V appears below as soon as you record data. Take at least 5 readings, then change the number of dry cells in step 1 and repeat to compare the graphs.

No.	I / A	V / V	Cells
No readings yet — record data to fill this table

3Graph of V against I

Reveal the actual values of this cell