7.0 Earth’s Magnetism

  Magnetism and Matter

Earth is a huge magnet. There are three components of earth’s magnetism

(i) Magnetic Declination $(?)$ The smaller angle subtended between the magnetic meridian and geographic meridian is called magnetic declination.

(ii) Magnetic Inclination or Magnetic Dip $(?)$ The smaller angle sub tended between the magnetic axis and horizontal is called magnetic inclination on magnetic dip.

(iii) Horizontal Component of Earth’s Magnetic Field $(H)$ If $B$ is the intensity of earth’s magnetic field then horizontal component of earth’s magnetic field $H = B$ $cos ?$

It acts from south to north direction.

Vertical component of earth’s magnetic field

$$V = B\ sin ?$$$$?\ B = \sqrt{H^2+ V^2}$$

and $$tan ? =\frac{V}{H}$$

Angle of dip is zero at magnetic equator and $90°$ at poles.