(a) Name and state the law which relates the potential difference and current in a conductor.
(b) What is the necessary condition for a conductor to obey the law named above in part (a)?

(a)Ohm’s law is the name of the law. The current flowing through a conductor is exactly proportional to the potential difference at its ends, assuming that the conductor’s physical parameters and temperature stay unchanged.

(b) In order for a conductor to obey Ohm’s law, the temperature must remain constant.