Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.
Wind is an air movement having both direction and speed. Depending on the cause of the winds, they can blow in many directions.The Easterly winds blow from east to west whereas the westerly winds blow from west to east.
EXAMIANS