Which of the following is not application of superconductors?
a. Superconducting generators are smaller in size and weight in comparison with conventional generators.
b. Superconductors can be used as memory or storage elements in computers.
c. Superconductors magnets have been used to letitate trains above its rails.
d. None of the above.

HintFirstly we have to observe the type of question that has been asked, which is a property based question. In this question first we have to sort out what exactly are the semiconductor materials. Then we have to write its properties and characteristics so that we can compare it with options and get the answer.

Complete step-by-step solution:
Superconductors: Superconductors are the substances that allow the free flow of electricity, i.e. provides either none or negligible resistance when they become colder than a certain temperature called “Critical Temperature”. At this temperature there is free flow of electrons in the material.
The applications of superconductors are as follows:
i) Superconducting generators are much smaller in comparison to the conventional generators when compared in size and weight.
ii) Magnets that have been used to levitate trains above its rails are also superconducting nature.
iii) Superconducting magnetic propulsion systems are the systems that could be used to launch satellites into orbits. They don’t even need rockets for the job.
iv) High efficiency ore-separating machines may be built using superconducting magnets which can be used to separate tumor cells from healthy cells. They use the high gradient magnetic separation method for it.
v) Since the current in a superconducting wire can flow without any change in magnitude, it can be used for transmission lines.
vi) Superconductors are the newer technology that are used as memory or storage elements in computers.
Hence, D is the correct answer.

Note: Semiconductor material doesn't just minimize the resistance, but along with that they also cut the energy losses to nearly zero. This happens when they are lowered to extremely low temperatures.