What are the Earth magnetic elements defined ? And which are they ?
To obtain the complete information about the Earth's magnetic field and its value and its direction at any place on the surface of the Earth three magnetic elements are defined. They are :
$(1)$ Magnetic declination : $(D)$
$(2)$ Magnetic dip angle: $(I)$
$(3)$ Two components of Earth's magnetic field.
$(a)$ Horizontal component $\mathrm{H}_{\mathrm{E}}$ and
$(b)$ Vertical component $Z_{\mathrm{E}}$
Answer the following questions regarding earth’s magnetism:
$(a)$ A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth’s magnetic field.
$(b)$ The angle of dip at a location in southern India is about $18^o$. Would you expect a greater or smaller dip angle in Britain?
$(c)$ If you made a map of magnetic field lines at Melbourne in Australia, would the lines seem to go into the ground or come out of the ground?
$(d)$ In which direction would a compass free to move in the vertical plane point to, if located right on the geomagnetic north or south pole?
$(e)$ The earth’s field, it is claimed, roughly approximates the field due to a dipole of magnetic moment $8 \times 10^{22}\; J\, T^{-1}$ located at its centre. Check the order of magnitude of this number in some way.
$(f)$ Geologists claim that besides the main magnetic $N-S$ poles, there are several local poles on the earth’s surface oriented in different directions. How is such a thing possible at all?
At a point $A$ on the earth's surface the angle of $\operatorname{dip}, \delta=+25^{\circ} .$ At a point $B$ on the earth's surface the angle of dip, $\delta=-25^{\circ} .$ We can interpret that
Give information about Earth’s magnetism.
Dip angle in vertical plane at an angle ${\cos ^{ - 1}}\,\left( {\frac{1}{{\sqrt 2 }}} \right)$ from magnetic meridian is $60^o$, then actual dip at that place
How many neutral points will be obtained when a bar magnet is kept with magnetic moment parallel to earth's magnetic field?