While planning to verify Ohm’s law in the laboratory, a student prepared the following outline.
• Power supply: 0–6 V d.c. source
• Components: rheostat, key, ammeter, voltmeter, unknown wire X
• Range of current to be used: up to 0.8 A
Answer the questions that follow.
(a) Draw a neat labelled circuit diagram suitable for this experiment.
(b) Describe the step-by-step experimental procedure the student should follow to obtain at least five sets of V and I readings.
(c) List any three precautions that must be observed to keep the temperature of wire X nearly constant during the experiment.
(d) Suppose the graph plotted from the readings gives a straight line whose slope is 5.4 Ω. Calculate the resistance of wire X and comment on how this value relates to Ohm’s law.