Electromagnetic radiation and B fields in EMR are in-phase (see math section below). An important aspect of light's nature is its frequency. The frequency of a wave is its rate of oscillation and is measured in hertz, the SI unit of frequency, where one hertz is equal to one oscillation per second. Light usually has multiple frequencies that sum to form the resultant wave. Different frequencies undergo different angles of refraction, a phenomenon known as dispersion. A wave consists of successive troughs and crests, and the distance between two adjacent crests or troughs is called the wavelength. Waves of the electromagnetic spectrum
The Crests Jarmels. Former Jarmels member Ray Orta was also called in as a fill-in replacement for Joe Rivera. On December 12, 2017, J.T. Carter's Crests performed at The Paramount Theatre in Asbury Park, New Jersey, along with over 40 other groups from the 1950s and '60s, as part of TJ Lubinsky's new PBS TV Special, "Doo Wop Generations" (part of the "My Music" series). The special aired nationally in the US on PBS on March 3, 2018. The group was featured singing "The Angels Listened In" on the PBS television broadcast, as well as "Step By Step" listed on the CD/DVD