A toroidal solenoid has a central radius of 0.50 m and a cross-sectional diameter of 10 cm. When a current passes through the coil of the solenoid, the magnetic field inside the solenoid at its CENTER has a magnitude of 2.0 μT. What is the largest value of the magnetic field inside the solenoid when this current is flowing? (μ0 = 4π × 10^−7 T • m/A)

a. 1.8 micro T
b. 0.50 micro T
c. 2.8 micro T
d. 2.2 micro T
e. 3.5 micro T

To solve this problem we will apply the concepts related to the magnetic field. From the magnetic field we will compare what happens with the distance or the radius between the bodies and we will make the replacement with the values we have. The largest value of magnetic field,

Here,

= Permeability at free space

N = Number of loops

I = Current

R = Radius

From this relation we can conclude that the radius is inversely proportional to the Magnetic field, then

If we let the another values as constant we have that the relation between two magnetic field is,

Replacing,

Therefore the correct option is

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia