Human Ear and Hearing Range

Humans hear 20 Hz to 20,000 Hz (20 kHz). Below 20 Hz: Infrasonic (elephants, earthquakes use this). Above 20,000 Hz: Ultrasonic (bats, dolphins, SONAR, medical imaging — USG). Ear: Pinna → Ear canal → Eardrum (tympanic membrane) → Ossicles (3 tiny bones: Malleus, Incus, Stapes) → Cochlea → Auditory nerve → Brain.