Back to Top. 1  These are the waves which are having the lowest frequency in the electromagnetic spectrum. They are given out by transmitter. 2  They are formed as a result of thunder, lightning etc. 3  They are used in communication mostly.  They are of four types of radio waves 1  namely: Long wave.  Medium 1  wave. Ultra high frequency  (UHF)
What is the role of arsenic in the mining industry . Arsenic is a naturally occurring element commonly found as an impurity in metal ores, and is produced commercially for use in pesticides, wood preservatives, and , Get Price arsenic - definition of arsenic by Medical dictionary
Arsenic (chemical symbol As) occurs naturally in soil and bedrock in many parts of the United States, including parts of Massachusetts. During the 1800s it was mined commercially in New Hampshire, but since 1985 arsenic used in the U.S. has been imported.Activities that could have left arsenic residuals include apple orchard spraying, coal ash disposal, and use of some pressure treated wood.uring the 1800s it was mined commercially in New Hampshire, but since 1985 arsenic used in the U.S. has been imported. Activities that could have left arsenic residuals include apple orchard spraying, coal ash disposal, and use of some pressure treated wood.