Human Ear Mechanism — Homi Bhabha Class 9 Physics MCQs with Solutions

Solution: Sound waves make the eardrum vibrate; these vibrations are then passed on and amplified.

Solution: The hammer, anvil and stirrup amplify the eardrum's vibrations and pass them to the cochlea.

Solution: The fluid-filled cochlea contains sensory cells that turn vibrations into nerve impulses sent to the brain.

Solution: The pinna (outer ear) gathers sound and directs it into the ear canal.

Solution: Sound is collected by the pinna, travels down the ear canal to the eardrum, is amplified by the ossicles, converted in the cochlea, and carried by the auditory nerve.

Solution: Humans hear roughly 20 Hz to 20 kHz; below is infrasound and above is ultrasound.

Solution: The fluid-filled cochlea in the inner ear contains tiny hair cells that convert the vibrations into electrical nerve impulses, which the auditory nerve carries to the brain.

Solution: The human audible range runs roughly from 20 Hz (lowest) to 20,000 Hz (highest). Below this is infrasound and above it is ultrasound, both inaudible to us.

Solution: The pinna gathers sound into the ear canal, which strikes the eardrum. The eardrum passes vibrations to the three ossicles, then to the cochlea, and finally the auditory nerve carries signals to the brain.

Solution: The same vibration force is collected over the large eardrum and delivered to the tiny oval window. Because pressure = force / area, focusing the force onto a smaller area raises the pressure, so the faint vibrations are strong enough to move the inner-ear fluid.