To develop this problem it is necessary to apply the concepts related to Sound Intensity.
By definition the intensity is given by the equation

Where,
I = Intensity of Sound
= Intensity of Reference
At this case we have that 15 engines produces 15 times the reference intensity, that is

And the total mutual intensity is 100 dB, so we should




Therefore each one of these engines produce D. 88dB.
Answer:
C
Explanation:
b is 55 miles per hour south or 55mph[South]
the important part to understand is that velocity is a vector meaning it also has to have a direction, in this case south. That is why a (2m/s) is not a velocity, however 2m/s is a speed.
Answer: Electromagnetic waves (Ultraviolet light, between 100 nm and 380 nm)
Explanation:
Solar cells work by the photoelectric effect, which consists of the emission of electrons (electric current) when light (electromagnetic waves) falls on a metal surface under certain conditions.
In this sense, the portion of the electromagnetic spectrum this cells use is Ultraviolet light (UV) from the Sun, whose wavelength is approximately between 100 nm and 380 nm.
It is important to note, this is a type of electromagnetic radiation that is not visible to the human eye.
They both have a magnetic field