The primary responsibilities of human resources are: 1  C - Compensation. 2  H - Human resource development. 3  E - Employee and labor relations. 4  S - Safety and health. 5  S - Staff.
A new technique uses sound waves to levitate objects and move them in mid-air. Credit: Dimos Poulikakos View full size image. View full size image. Hold on to your wand, Harry Potter: Science has outdone even your best Leviosa! levitation spell.
But by definition radio waves are not sound waves. Radio waves can travel in a vacuum, but sound waves need a physical medium. To explain â¦ the apparent contradiction, the sound wave is converted to an electrical signal version that is then used to modulate the radio signal. 3 people found this useful. Asif Shaik.