Answer the following questions related to the conditions under which Ohm’s law is valid.
a. (i) Explain why a carbon resistor connected in an electric circuit follows Ohm’s law while a semiconductor diode does not.
b. (ii) State any two experimental conditions that must be maintained so that a metallic conductor continues to obey Ohm’s law.
c. (iii) Outline an experimental procedure to verify Ohm’s law for a given wire, mentioning the essential circuit components and the observation to be made.