If something vibrates one million times per second, its frequency is 1 megahertz (MHz).

Here's why:

* Frequency is the number of times a wave repeats itself in one second.

* Hertz (Hz) is the unit of measurement for frequency.

* Mega is a prefix meaning "million."

So, 1 million vibrations per second is equal to 1,000,000 Hz, which is the same as 1 MHz.