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:
q = 4.5 nC
Explanation:
given,
electric field of small charged object, E = 180000 N/C
distance between them, r = 1.5 cm = 0.015 m
using equation of electric field

k = 9 x 10⁹ N.m²/C²
q is the charge of the object

now,

q = 4.5 x 10⁻⁹ C
q = 4.5 nC
the charge on the object is equal to 4.5 nC
The pet store would be the reference point because it is where he started and it will not move. Hope this helped.
Answer:

Explanation:
We are given that
Linear charge density of wire=
Radius of hollow cylinder=R
Net linear charge density of cylinder=
We have to find the expression for the magnitude of the electric field strength inside the cylinder r<R
By Gauss theorem



Where surface area of cylinder=

A challenge scientists face with this process is the use of ultrathin iron oxide, to pull protons off water and produce hydrogen gas, which itself is a poor electrical conductor.