Which of the following statements is correct about the angle of dip at various points on Earth?

Analysis of the Question

This question tests your understanding of Terrestrial Magnetism, specifically the concept of the Angle of Dip (or Inclination). The angle of dip is the angle that the Earth's magnetic field lines make with the horizontal surface of the Earth.

Concept Explanation

The Earth acts like a giant bar magnet. Because of this, the magnetic field lines are not parallel to the ground everywhere:

1. At the Magnetic Equator: The magnetic field lines are parallel to the Earth's surface. Since the field lines are horizontal, the angle they make with the horizontal is 0°.
2. At the Magnetic Poles: The magnetic field lines point directly into (or out of) the Earth's surface (vertically). Therefore, the angle they make with the horizontal is 90°.
3. Between the Equator and the Poles: The angle of dip varies between 0° and 90° depending on your latitude.

Step-by-Step Solution

• Evaluate Option A: As explained above, at the equator, the magnetic field is horizontal (0° dip), and at the poles, it is vertical (90° dip). This matches the physical behavior of Earth's magnetic field.
• Evaluate Option B: The angle of dip is primarily a function of latitude, not altitude. This statement is incorrect.
• Evaluate Option C: While the dip direction changes, the standard definition of the angle of dip is the magnitude of the angle from the horizontal. It is not defined by a simple positive/negative sign convention across hemispheres in this context.
• Evaluate Option D: We know the angle changes from 0° at the equator to 90° at the poles, so it is definitely not constant.

Conclusion

Based on the principles of geomagnetism, the angle of dip is 0° at the magnetic equator and increases to 90° as you move toward the magnetic poles.

Exam Tip: Think of a compass needle. If you were at the magnetic equator, a perfectly balanced compass needle would stay perfectly horizontal. If you were at the North Pole, the needle would try to point straight down into the ground! This visual helps you remember that the dip is 0° at the equator and 90° at the poles.