A. At the magnetic pole of earth; angle of dip is 90° and BH = 0.
B. At the magnetic pole of earth; angle of dip is zero and Bv = 0.
C. At the magnetic equator of the earth; angle of dip is 90° and BH = 0.
D. At the magnetic equator of the earth; angle of dip is zero and Bv = 0.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A and D only
The angle of dip \( I \) is the angle the earth's field makes with the horizontal, so
\( \displaystyle \tan I = \frac{B_{V}}{B_{H}} \)
At the magnetic poles the field is vertical; at the magnetic equator it is horizontal.
(A) At the magnetic pole of earth; angle of dip is 90° and BH = 0. — Correct. The field is vertical at a pole, so \( I = 90^\circ \) and the horizontal component vanishes.
(B) At the magnetic pole of earth; angle of dip is zero and Bv = 0. — Incorrect. At a pole the field is entirely vertical, so \( B_V \) is the whole field, not zero.
(C) At the magnetic equator of the earth; angle of dip is 90° and BH = 0. — Incorrect. At the equator the field is horizontal, so the dip is zero and \( B_H \) is the whole field.
(D) At the magnetic equator of the earth; angle of dip is zero and Bv = 0. — Correct. The field is horizontal at the magnetic equator, so \( I = 0^\circ \) and \( B_V = 0 \).