What is the world's second best conductor?

Answer 1

The phrase "best conductor" is somewhat deceptive because conductance is often associated with resistivity. As an example, some consider Silver to be a better conductor than Gold because it has a slightly lower resitivity, but fail to take temperature into account. When electrical current passes through a conductor, it causes the conductor to heat up. As Silver heats up, it's resistivity remains relatively constant, but as Gold heats up, it's resistivity drops. So at room temperature, Silver appears to be a better conductor than Gold, but in pratice, Gold conducts better than Silver. Currently there is a new material known as Graphene that may turn out to be an even better conductor than either Gold or Silver. So when asked which conductor is best, the answer may soon be Graphene, followed by Gold, followed by Silver. Unless of course you mean "Which conductor has the lowest resistivity at room temperature?"