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.
The time gap between spring and neap is approximately 7 days. The neap tides refers to a period of moderate tides when the sun and moon are at right angles to each other. The spring tides are high tides.
EXAMIANS