A normal human ear can hear sound of frequency ________.

The correct answer is 20Hz - 20 kHz.

Key Points

• The normal human ear can hear sounds in the frequency range of 20Hz to 20 kHz.
• This range is considered the standard auditory range for humans, encompassing most of the sounds humans encounter daily.
• Sounds below 20Hz are known as infrasound, which typically cannot be heard by the human ear.
• Sounds above 20kHz are known as ultrasound, which also cannot be detected by the human auditory system.
• Hearing sensitivity varies among individuals, and the upper limit often decreases with age.

Additional Information

• Infrasound:
  • Infrasound refers to sound waves with frequencies below the lower limit of human audibility (<20Hz).
  • It can be generated by natural events like earthquakes and volcanic eruptions, as well as by certain animals for communication.
• Ultrasound:
  • Ultrasound refers to sound waves with frequencies above 20 kHz.
  • It is commonly used in medical imaging (e.g., ultrasound scans) and in industrial applications such as cleaning and detecting flaws in materials.
• Hearing Loss:
  • Hearing loss can affect the range of frequencies a person can hear, often reducing the upper limit.
  • Common causes include age-related hearing loss (presbycusis), noise exposure, and certain medical conditions.
• Decibels (dB):
  • Sound intensity is measured in decibels (dB), with normal conversation typically around 60 dB.
  • Prolonged exposure to sounds above 85 dB can cause hearing damage.