A long straight wire carrying a 4-A current is placed along the x-axis as shown in the figure.What is the magnitude of the $\vec { B }$ field at a point P,located at y = 2 cm,due to the current in this wire? (μ₀ = 4π × 10^-7 T ∙ m/A)

Question

Quizplus · Accepted Answer

The magnitude of the magnetic field at a point P, located at distance r from the wire carrying a current I is given by the formula: 
$\vec { B }=\frac { { \mu }_{ 0 }I }{ 2\pi r }$
In this case, the distance of the point P from the wire is r = 2 cm = 0.02 m, and the current in the wire is I = 4 A. Therefore, substituting these values in the above equation, we get:
$\vec { B }=\frac { (4\pi \times 10^{-7} T \cdot m/A)(4 A) }{ 2\pi (0.02 m) }=40 \mu T$ 
Hence, the correct choice is C.

A Long Straight Wire Carrying a 4-A Current Is Placed B⃗\vec { B }B

A Long Straight Wire Carrying a 4-A Current Is Placed $\vec { B }$