What is the magnetic field strength required to produce a flux density of 1mWb/m² in air?

Correct option is A

​$$\text{The relationship between magnetic flux density } (B) \text{ and magnetic field strength } (H) \text{ is:} \\[6pt]B = \mu H \\[10pt]\text{For air:} \\[6pt]\mu = \mu_0 = 4\pi \times 10^{-7} \ \text{H/m} \\[12pt]\textbf{Given:} \\[6pt]B = 1 \ \text{mWb/m}^2 = 1 \times 10^{-3} \ \text{Wb/m}^2 \\[12pt]\textbf{Calculation:} \\[6pt]H = \frac{B}{\mu_0} \\[8pt]H = \frac{1 \times 10^{-3}}{4\pi \times 10^{-7}} \\[10pt]H \approx \frac{1 \times 10^{-3}}{1.256 \times 10^{-6}} \approx 796 \ \text{AT/m} \\[8pt]H \approx 800 \ \text{AT/m}$$​​