Question

Draw a neat labelled diagram for angle of dip.

Write a short note on Earth’s magnetic field. Mention the extreme values of magnetic field at magnetic poles and magnetic equator.

Answer 1

i. Magnetic force experienced per unit pole strength is magnetic field \(\overset\rightarrow{B}\) at that place.

ii. This field can be resolved in components along the horizontal (\(\overset\rightarrow{B}_H\)) and along vertical (\(\overset\rightarrow{B}_v\)).

iii. The two components are related with the angle of dip (ø) as, B_H = B cos ø, B_v = B sin ø

\(\frac{B_v}{B_H}\) = tan ø

B² = \(B^2_v+B^2_H\)

∴ B = \(\sqrt{B^2_V+B^2_H}\)

iv. At the magnetic North pole: \(\overset\rightarrow{B}=\overset\rightarrow{B}_V\) directed upward, \(\overset\rightarrow{B}_H\) = 0 and ø = 90°.

v. At the magnetic south pole: \(\overset\rightarrow{B}=\overset\rightarrow{B}_V\) directed downward, \(\overset\rightarrow{B}_H\) = 0 and ø = 270°.

vi. Anywhere on the magnetic equator (magnetic great circle): B = B_H along South to North, \(\overset\rightarrow{B}_V\) = 0 and ø = 0