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

Here's why:

* Frequency is a measure of how often something repeats in a given time period.

* Hertz (Hz) is the standard unit of measurement for frequency. One Hertz means one cycle per second.

* Mega is a prefix meaning "million".

Therefore, 1 million vibrations per second is equivalent to 1 megahertz (MHz).