## Filters

Q&A - Ask Doubts and Get Answers
Q

# A long straight wire in the horizontal plane carries a current of 50 A in north to south direction. Give the magnitude and direction of B at a point 2.5 m east of the wire.

3. A long straight wire in the horizontal plane carries a current of 50 A in north to south direction. Give the magnitude and direction of B at a point 2.5 m east of the wire.

Views

The magnitude of the magnetic field at a distance r from a long straight wire carrying current I is given by,

$|B|=\frac{\mu _{0}I}{2\pi r}$

In this case

$|B|=\frac{4\pi \times 10^{-7}\times 50}{2\pi\times 2.5}$            (current=50A, distance= 2.5m, permeability of free space = 4$\pi \times$10-7 TmA-1)

$\\=4\times10^{-6}T$

The current is going from the North to South direction in the horizontal plane and the point lies to the East of the wire. Applying Maxwell's right-hand thumb rule we can see that the direction of the magnetic field will be vertically upwards.

Exams
Articles
Questions