Humans can hear sounds within a specific range of frequencies, typically between 20 Hz and 20,000 Hz. Sounds with frequencies below this range are referred to as infrasound, while sounds with frequencies above this range are called ultrasound. Therefore, high-frequency sounds beyond the range of human hearing are considered ultrasound.
Similarly, humans can see light within a specific range of frequencies, known as the visible light spectrum. The visible light spectrum ranges from approximately 430 trillion Hz (terahertz) to 750 trillion Hz, corresponding to the colors violet through red.
The speed at which light travels is a constant in a vacuum and is approximately 299,792 kilometers per second (or about 186,282 miles per second). This value is commonly denoted as the speed of light (c). When light travels through a medium other than a vacuum, such as air or water, its speed is slightly slower, but for the sake of simplicity, let's assume we're discussing light in a vacuum.
Given the speed of light, the time it takes for light to travel from an object to our eyes depends on the distance between the object and ourselves. This can be calculated using the formula:
Time = Distance / Speed
For example, if the object is located 100,000 kilometers away, the time it would take for light to reach us would be:
Time = 100,000 km / 299,792 km/s ≈ 0.333 seconds
So, it would take approximately 0.333 seconds for light from that object to travel to our eyes.
It's important to note that the perception of light and sound is not solely determined by their speed of propagation. The properties of our sensory organs, such as the eyes and ears, and the processing capabilities of our brain also play crucial roles in our ability to perceive and interpret these stimuli.