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 Thermosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions. It is therefore known as Ionosphere. The temperature here starts increasing with heights. Radio waves transmitted from the earth are reflected back to the earth by this layer. The International Space Station and other satellites orbit in this layer. Auroras are observed in the lower parts of this layer.
EXAMIANS