What sound Cannot be heard by humans?
Any frequency below 20 Hz is called infrasound and any frequency above 20 kHz is called ultrasound. These are inaudible sounds. So, we cannot hear inaudible sounds, ultrasound, and infrasound.
Though generally thought to be rare, a new study suggests that one particular form of this condition—hearing sounds from flashes of light—may be more common than once thought, reports Hannah Devlin for The Guardian.
Light does not produce sound because it is not a vibration on a material.
Light is made of vibrations in the electric and magnetic fields. Now, the timescale (for example, the oscillation speed or the wave speed) for light is much faster than that for sound, so sound doesn't even notice when light is around.
There is a genuine auditory experience enabled by a functional auditory system when we hear silence. But there is no auditory experience possible at all when the auditory system is malfunctioning (as in the case of deafness), and therefore it is also not possible to hear silence under such a condition.
Consonants such as “s,” “h,” and “f,” which have higher frequencies and are harder to hear. Because consonants transmit the majority of the meaning in speech, it would only make sense that those with high-frequency hearing loss have trouble following conversations.
No, you cannot hear any sounds in near-empty regions of space. Sound travels through the vibration of atoms and molecules in a medium (such as air or water). In space, where there is no air, sound has no way to travel.
You'll always see lightning before you hear it, because typically lightning will be a mile away, two miles away. That's a great enough distance that that speed difference becomes apparent to your brain.
We can hear gravitational waves, in the same sense that sound waves travel through water, or seismic waves move through the earth. The difference is that sound waves vibrate through a medium, like water or soil. For gravitational waves, spacetime is the medium. It just takes the right instrument to hear them.
The commonly stated range of human hearing is 20 to 20,000 Hz. Under ideal laboratory conditions, humans can hear sound as low as 12 Hz and as high as 28 kHz, though the threshold increases sharply at 15 kHz in adults, corresponding to the last auditory channel of the cochlea.
Can all sounds be heard by humans?
Humans can generally sense sounds at frequencies between 20 and 20,000 cycles per second, or hertz (Hz)—although this range shrinks as a person ages. Prolonged exposure to loud noises within the audible range have long been known to cause hearing loss over time.
Phonophobia is defined as a persistent, abnormal, and unwarranted fear of sound. Often, these are normal environmental sounds (e.g., traffic, kitchen sounds, doors closing, or even loud speech) that cannot under any circumstances be damaging.