Question

Earth's magnetic field always has a horizontal component except at

• A. Magnetic poles
• B. Magnetic equator
• C. Geographical north pole
• D. At an altitude of 45^o

Answer 1

The correct option is A

Magnetic poles

Explanation for the correct answer:-

Option (A)

Direction of the earth’s magnetic field,

1. The tangent to the magnetic field lines at that point gives the direction of earth's magnetic field.
2. The magnetic field will have a component along the surface of the earth if the tangent is not perpendicular to the surface of the earth at that point.
3. This component is called the horizontal component of the earth’s magnetic field at that point.

Magnetic poles,

1. Magnetic field lines are completely perpendicular to the surface of the earth and so is the tangent to the field lines at the magnetic poles.
2. Therefore, the direction of the magnetic field at the magnetic poles is completely perpendicular to the surface of the earth and hence, has no component that is parallel to the surface of the earth.
3. Therefore, the horizontal component of the earth’s magnetic field is zero at the magnetic poles.
4. Hence, Earth’s magnetic field always has a horizontal component except at the magnetic poles where it is zero.

Hence Option (A) is the correct answer.