This is an amount sufficient to block almost all astronomical X-rays and also astronomical gamma rays—see below.
The frequencies are in the mid 10 14 scales.
The generation of electromagnetic radiation is separated into two categories.
The light that excites the human is a very small portion of the electromagnetic spectrum.
This suggested that there was a connection between electricity and magnetism, and inspired additional work by scientists such as Faraday, Ampère, Volta, and Ohm all of whom now have electricity-related units named after them.
The collective range of possible lights is called the electromagnetic spectrum.