Answer:
a. 
b. 
c. 
Explanation:
First, look at the picture to understand the problem before to solve it.
a. d1 = 1.1 mm
Here, the point is located inside the cilinder, just between the wire and the inner layer of the conductor. Therefore, we only consider the wire's current to calculate the magnetic field as follows:
To solve the equations we have to convert all units to those of the international system. (mm→m)

μ0 is the constant of proportionality
μ0=4πX10^-7 N*s2/c^2
b. d2=3.6 mm
Here, the point is located in the surface of the cilinder. Therefore, we have to consider the current density of the conductor to calculate the magnetic field as follows:
J: current density
c: outer radius
b: inner radius
The cilinder's current is negative, as it goes on opposite direction than the wire's current.




c. d3=7.4 mm
Here, the point is located out of the cilinder. Therefore, we have to consider both, the conductor's current and the wire's current as follows:

As we see, the magnitud of the magnetic field is greater inside the conductor, because of the density of current and the material's nature.
Answer:
(1) Resonance
Explanation:
Resonance is the process whereby a system is set into vibration due to the vibration of a nearby system with larger amplitude. The frequency at which this vibration takes place is called the resonant frequency.
It is a phenomenon of amplification that occurs when the frequency of a periodically applied force is in harmonic proportion to the natural frequency of the system on which it acts.
the answer is d they are essential to all ecosystems
The difference between conductors and insulators is because
of electronic structure of atoms and molecules.
Anywhere we have free electrons, we have a hard conductor
where free electrons help in conduction.
In electrolytes, charged Ions do conduction.
Dielectrics (or insulators) don't have free electrons current.
Free electrons mean, the electrons that are not related with
a specific atom, they are allowed to move nearby the crystal lattice.