Same current ''i'' is flowing in three infinitely long wire along positive x, y and z directions. The magnetic field-at a point (0,0-a) would be

Magnetic field due to current along the z-axis is 0. and due to rest two wires is $\frac{\mu_0}{2\pi} \frac{i}{a}$ $B=\frac{\mu_0\,i}{2 \pi\,a}j$ $B_y=\frac{\mu_0\,i}{2 \pi\,a}(-\hat{i})$ $B_z=0$

$\frac{\mu_0 i}{2\pi a}(\hat{j}-\hat{i})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}+\hat{j})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}-\hat{j})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}+\hat{j}+\hat{k})$

Same current ''i'' is flowing in three infinitely long wire along positive x, y and z directions. The magnetic field-at a point (0,0-a) would be

$\frac{\mu_0 i}{2\pi a}(\hat{j}-\hat{i})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}+\hat{j})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}-\hat{j})$

$\frac{\mu_0 i}{2\pi a}(\hat{i}+\hat{j}+\hat{k})$

Same current ''i'' is flowing in three infinitely

Notes on the earth's magnetic field

Concepts Used:

Earth’s Magnetic field

The Earth's magnetic field stretches millions of kilometers into space and resembles a bar magnet. The earth's magnetic pole is positioned between the Northern Pole and the North Pole's Antarctic magnets. That is why a compass magnet's north pole points north (north and south poles attract).

The Earth's magnetic field extends far and wide, but it is very small in terms of field power. It has a field power of merely 40,000 nT as compared to a refrigerator magnet which has a power of 107 nT.

Theory of Earth’s Magnetism

The Dynamo Effect: The outer core of the earth has molten Iron and other heavy elements in liquid form. The inner core solidifies under the influence of gravity. Therefore, the motion of metallic fluids in the outer core of the earth causes an electric current. Thus, the earth gets its own magnetic field lines.
Ionization of the Outer Layers: This theory tells us that the rotation of the earth in its own axis produces strong electric current due to the ionization of the outer layers of earth. This produces magnetism due to the movement of the ions. However, the magnetic field will be very weak. The Dynamo Effect is the more acceptable theory.

Components of Earth’s Magnetic Field

These are the components that are responsible for the magnitude and direction of the magnetic field of the earth at a given location:

Magnetic Declination
Horizontal Component of Earth’s Magnetic Field
The angle of Dip or Magnetic Inclination

	List- I (Layer of atmosphere)		List- II (Approximate height over earth's surface)
A.	F₁-Layer	I.	10 km
B.	D-Layer	II.	170-190 km
C.	Troposphere	III.	100 km
D.	E-layer	IV.	65-75 km

Same current ''i'' is flowing in three infinitely long wire along positive x, y and z directions. The magnetic field-at a point (0,0-a) would be

The Correct Option is A

Solution and Explanation

Top Questions on the earth's magnetic field

Notes on the earth's magnetic field

Concepts Used:

Earth’s Magnetic field

Theory of Earth’s Magnetism

Components of Earth’s Magnetic Field

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