The angle of dip at a location in Southern India is about 18°. Which of the following is correct for dip angle in Britain?
(A) Dip angle will be greater in Britain than in India.
(B) Dip angle will be smaller in Britain than in India.
(C) Nearer the place to the poles, lesser is the dip angle.
(D) Nearer the place to the poles, more is the dip angle.
(E) Dip angle is also called the angle of declination.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) and (D) only
The earth’s field resembles that of a bar magnet at its centre. Near the magnetic equator the field lines are horizontal, so the angle of dip is about \( 0^\circ \); near the magnetic poles they are vertical, so the dip is about \( 90^\circ \). The dip therefore increases as one goes from the equator towards the poles, from \( \tan\delta = V/H \) with H falling and V rising.
Southern India is close to the magnetic equator (dip about \( 18^\circ \)) and Britain is far nearer to the north magnetic pole.
(A) Dip angle will be greater in Britain than in India — Correct. Britain is at a higher magnetic latitude.
(B) Dip angle will be smaller in Britain than in India — Incorrect. It is the opposite.
(C) Nearer the place to the poles, lesser is the dip angle — Incorrect. The dip increases towards the poles.
(D) Nearer the place to the poles, more is the dip angle — Correct. It reaches \( 90^\circ \) at the magnetic poles.
(E) Dip angle is also called the angle of declination — Incorrect. The dip angle (inclination) is the angle between the earth’s total field and the horizontal. The angle of declination is the angle between the magnetic meridian and the geographic meridian.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Exercises – “… (b) The angle of dip at a location in southern India is about 18°. Would you expect a greater or smaller dip angle in Britain?”
Magnetic Declination and Dip – “… If a magnetic needle is perfectly balanced about a horizontal axis so that it can swing in a plane of the magnetic meridian, the needle would make an angle with the horizontal (Fig. 5.10). This is known as the angle of dip (also known as inclination).”
Magnetic Declination and Dip – “… At the magnetic poles such a needle will point straight down.”