When cooled below 4.2 K, mercury becomes a superconductor, which means it has no electrical resistance. When a current is passed through mercury under these conditions, which of the following effects will be present?
A. 1 and 3 only
B. 1, 2 and 3
C. 2 only
D. 3 only
E. 1 only
Let’s look at each situation:
In the case that there is no electrical resistance, we can conclude that no thermal energy can be released- therefore we can say there will also be no thermal effect.
Since Mercury is a single element acting as the conductor, we also can conclude there can be no possible chemical effect.
Although, since Mercury is a metal, and there is electricity or current passed through it- we know that if there is electricity and a metal, there will surely be magnetism. Therefore, 3 is the only correct choice and our answer is D.