Question

a scientist observes that the electrical resistance of a superconducting material drops to zero when the material is cooled to very low temperatures. which of the following statements best describes what the scientist is observing?
the scientist is observing the electrical power of a superconductor.
the scientist is observing the temperature of a superconductor.
the scientist is observing an intensive property of a superconductor.
the scientist is observing an extensive property of a superconductor.

Explanation:

Intensive properties do not depend on the amount of the substance. The transition of a superconducting material to zero - resistance at low temperatures is an inherent property of the material itself and does not depend on the quantity of the superconductor. Electrical power is related to current and voltage ($P = VI$), and that's not what's being observed here. The temperature is just the condition triggering the observation, not the main property being observed. Extensive properties depend on the amount of the substance, which is not the case for the zero - resistance property of a superconductor.

Answer:

The scientist is observing an intensive property of a superconductor.