H = ____is the expression for the magnetic field due to an infinite linear current-carrying conductor

• A. (I ⁄ 2Πr) A/m
• B. (μI ⁄ 2Πr) A/m
• C. (I ⁄ 2r) A/m
• D. (μI ⁄ 2r) A/m

Answer: (A)

Magnetic Field Strength (H)  gives the quantitative measure of strongness or weakness of the magnetic field.
H = B/μo
Where
B = Magnetic Flux Density
μo = Vacuum Permeability
Magnetic field due to infinite Linear current-carrying conductor is
B = μoI/2πr
B/μo = I/2πr
H = (I/2πr)A/m