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 amount of insolation received varies from latitude to latitude. The Regions within the equator and 40° N and S latitudes are energy surplus regions because they receive abundant sunlight and hence more heat will be gained than lost.The Regions beyond 40° N and S latitudes are energy deficit regions because they lose more heat than that gained from sunlight.
EXAMIANS