The SI unit of intensity of sound is the decibel (dB). It is a logarithmic unit that expresses the ratio of a physical quantity (in this case, the intensity of sound) to a reference value. The reference value for sound intensity is the threshold of human hearing, which is 0 dB. A sound intensity of 120 dB is 100 times more intense than the threshold of human hearing, and a sound intensity of 140 dB is 1000 times more intense than the threshold of human hearing.
Decibels are often used to measure the loudness of sound. However, it is important to note that decibels are not a linear measure of loudness. A sound that is 10 dB louder than another sound is not twice as loud, it is 10 times louder.
The other options are not correct. Newton is the SI unit of force, heartz is the SI unit of frequency, and tesla is the SI unit of magnetic flux density.