Answer:
Area under a curve can be estimated via block counting, calculated with simple geometry if the velocity has constant accelerations, or calculated by integration if the velocity can be described by a mathematical equations.
The area under a velocity time curve will be the product of velocity and time which equals displacement.
To solve this problem we will start from the definition of the decibels which refers to the log relationship of the intensities, mathematically each decibel of the people can be described as follows
For properties of the logarithm then we have that,
We have the relation
The related concept to solve this exercise is given in the expressions that the magnetic field has both as a function of the number of loops, current and length, as well as inductance and permeability. The first expression could be given as,
The magnetic field H is given as,
Here,
n = Number of turns of the coil
I = Current that flows in the coil
l = Length of the coil
From the above equation, the number of turns of the coil is,
The magnetic field is again given by,
Where the minimum inductance produced by the solenoid coil is B.
We have to obtain n, that
Replacing with our values we have that,
Therefore the number of turn required is 28Truns