Question

Find the magnetic flux density when a point from a finite current length element of current 0.5A and radius 100nm.

• A. 7
• B. 5
• C. 1
• D. 0

Answer 1

Answer: (C)

1

Answer 2

The magnetic flux density (B) due to a long straight current-carrying wire is calculated using the formula $B = \frac{\mu_0 I}{2\pi r}$. Given current $I = 0.5 \text{ A}$ and distance $r = 100 \text{ nm} = 10^{-7} \text{ m}$, and using the permeability of free space $\mu_0 = 4\pi \times 10^{-7} \text{ T m/A}$, the calculation yields $B = \frac{(4\pi \times 10^{-7}) \times 0.5}{2\pi \times 10^{-7}} = 1 \text{ T}$.