Ac (Noun)

A radioactive element of the actinide series; found in uranium ores.

Nouns denoting substances.

Actinium is a radioactive element of the actinide series that is found in uranium ores and is highly unstable.
The team of scientists spent years studying the properties of actinium and its potential applications in medicine.
Actinium was first discovered in 1902 by French chemist André-Louis Debierne, who isolated it from pitchblende ore.
The most common isotope of actinium is Ac-227, which has a half-life of 21.77 years and decays primarily by beta emission.
Due to its highly radioactive nature, actinium is not found in its elemental form in nature, but rather as a component of uranium ores.

An electric current that reverses direction sinusoidally; "In the US most household current is AC at 60 cycles per second".

Nouns denoting natural phenomena.

Most power stations generate AC electricity as it is easier to transform and transmit than DC.
In contrast, a device like a laptop operates on DC but must first convert the incoming AC.
Most audio signals, especially from CDs, cassette tapes, and AM and FM radios, are analog and have been generated or processed in the AC domain.
Power electronics engineers and power engineers who specialize in this field must often go between DC and AC technologies and use electronic components to modify their working mode to DC-AC.
Typical domestic lighting circuits operate on an AC voltage that cycles in sinusoidal wave pattern between the zero volt value to peak voltages which range in typical distribution to several hundred volts.