Magnetostatics

Step 1: Understanding the Concept:
The magnetic intensity (also called the magnetizing field) is related directly to the total induced magnetic field and the properties of the core material (its permeability ).

Step 2: Key Formula or Approach:
The relationship between Magnetic Field ( ) and Magnetic Intensity ( ):

The permeability of the material is , where is relative permeability.


Step 3: Detailed Explanation:
Given values:
Relative permeability, .
Magnetic field, .
Permeability of free space, .
Calculate the magnetic intensity :





Bringing the power of 10 to the numerator:
.
The problem states that the magnetic intensity is .
Equating our result to this format:
.
Thus, the value of is .

Step 4: Final Answer:
The value of is .

Concept:
When current flows only along the surface
of a long cylinder, it behaves like a hollow cylindrical conductor
. Magnetic field is determined using Ampere’s circuital law
.

Step 1: Magnetic Field Inside the Cylinder ( )
For any Amperian loop inside the cylinder: By Ampere’s law: Thus, magnetic field is zero everywhere inside
, including along the axis. Statement (A) is correct
Statement (D) is incorrect
Statement (E) is incorrect

Step 2: Magnetic Field at the Surface ( )
Just outside the surface: This is the maximum
value of magnetic field. Statement (C) is correct
Statement (B) is incorrect

Final Conclusion:
Correct statements are .