Curie Temperature

# The temperature above which a ferromagnetic substance becomes paramagnetic is called:
A. Joule’s point
B. Curie Point
C. Ambient point
D. Maxwell point

The correct answer is B. Curie Point.

Curie point, also called Curie Temperature, the temperature at which certain magnetic materials undergo a sharp change in their magnetic properties. In the case of rocks and minerals, remanent magnetism appears below the Curie point—about 570 °C (1,060 °F) for the common magnetic mineral magnetite. This temperature is named for the French physicist Pierre Curie, who in 1895 discovered the laws that relate some magnetic properties to change in temperature.