Final answer:
The decibel is named after Alexander Graham Bell, with 'deci-' meaning one-tenth, making a decibel one-tenth of a Bel. Decibels quantify loudness because our perception of sound is logarithmic. Amplitude affects loudness, but decibels provide a more accurate measure as it correlates with our hearing perception.
Step-by-step explanation:
The term decibel (dB) gets its name from the prefix “deci-” which means one-tenth, in combination with “Bel”, named after Alexander Graham Bell, the inventor of the telephone. Therefore, a decibel is one-tenth of a Bel, a unit of measure for sound intensity. In essence, the decibel is named after a scientist, making option a) the correct choice.
Decibels are used to describe the loudness of sound because the human ear perceives loudness in a logarithmic manner. The loudness of a sound is often referred to as the sound intensity level or the decibel level. For instance, normal human conversation typically occurs at about 60 dB, while a whisper is around 30 dB, and a rock concert can reach levels of 110 dB or more.
Amplitude influences the loudness or volume of a sound; a sound wave with greater amplitude will sound louder. However, because the perceived loudness of sound by humans is more accurately described by the logarithm of the intensity, we use decibels rather than just amplitude to quantify sound levels.