The strength (frequency) or power of the sound that human ear can hear is measured in terms of Hertz Human can hear sound frequen cies between 20 to 20,000 Hertz. Any frequency beyond 20,000 Hertz is called Ultrasound as human cannot hear. Some animals can hear high frequency sounds (ex-Dogs and bats). In medical Ultrasound we use that we cannot hear which are measured in Mega Hertz.
Henna (mehndi)
13 years ago
