What is Angle of Dip?
The angle of dip is also sometimes called the magnetic dip and is defined as the angle which is made by the earth’s magnetic field lines with the horizontal.
The angle of dip usually is said it varies from point to point by providing the information which is related to the movement of the earth’s magnetic field. The angle of dip is said to be positive when the magnetic field points in the direction that is downwards. When the magnetic field points towards upward direction then the angle of dip is said to be negative.
The angle of dip is 0° when the needle of the dip rests horizontally while the angle of dip is 90° when the needle of dip rests vertically.
When the component that is horizontal and the vertical component of the earth’s magnetic field are equal the angle of dip is equal to 45°.
Magnetic Dip
Geomagnetics is that branch of geophysics concerned with all aspects of the magnetic field which is of earth’s that is including its origin, variation through time and manifestations in the form of magnetic poles. The remnant of the magnetization of rocks and local or the regional magnetic anomalies. The latter generally reflects the difference which is between theoretical and observed magnetic intensities at points of measurement with a magnetometer. When plotted on a magnetic map, it is known as an aeromagnetic map if the magnetometer was flown across the area. The anomalies provide the basis for inferences that are about probable subsurface structure and composition.
The magnetic dip or the dip angle or the magnetic inclination is the angle made with the horizontal by the line of the earth's magnetic field. This angle generally varies at different points on the surface of the earth. The positive values of inclination indicate that the earth's magnetic field is pointing downward into the Earth that too at the point of measurement. And the value if negative indicates that it is pointing upward. The dip angle is said to be in principle the angle which is made by the needle of a vertically held compass. In practice, ordinary compass needles may be weighted against dip or may be unable to move freely in the correct plane. The value of it can be measured even more reliably with a special instrument typically called a dip circle.
In 1544 the angle which is the dip was discovered by the engineer Georg Hartmann. A method which measures it with a circle of dip was described by Robert Norman in England in 1581.
Magnetic Inclination
Magnetic dip results from the tendency of a magnet to align itself with lines of the magnetic field. As the planet's magnetic field lines are not parallel to the surface, the northern end of a compass needle will point downward. That is in the northern hemisphere it is a positive dip or upward while in the southern hemisphere it is a negative dip. The range of dip is from -90 degrees at the North Magnetic Pole to +90 degrees at the South Magnetic Pole. The contour lines along which the dip measured at the planet's surface is equal are referred to as isoclinic lines. The points locus which is having a zero dip is known as the magnetic equator or aclinic line.
The dip angle which is also called magnetic dip or magnetic Inclination is the angle made by our planet's magnetic field lines with the horizontal. The angle of dip generally varies from point to point at the surface of the earth and provides information about the movement of the earth’s magnetic field.
The phenomenon is especially very important in aviation as it causes the compass of the airplane to give erroneous readings during banked turns and airspeed changes. The latter errors generally occur because the card of the compass tilts on its mount when under acceleration.
The needle compasses are often weighed during manufacture to compensate for magnetic dip so we can say that they will balance roughly horizontally. This balancing is usually said to be latitude-dependent.
Angle of dip, commonly known as magnetic dip, is the angle formed by the earth's magnetic field lines intersecting the horizontal.when the horizontal component and the vertical component of the earth's magnetic field are equal.
The angle of declination between the magnetic field and the horizontal is measured in the vertical plane aligned with magnetic north.
The compass needle is said to point to the magnetic north pole by a lot of people.
This is not geographically true. The compass at that position points in the direction of the horizontal component of the earth's magnetic field. The geomagnetic field and dip graphics below show how the compass needle aligns with the Earth's magnetic field lines.
Magnetic declination is the angle formed by true north (the line leading to the geographical North Pole) and the compass's direction of travel points (the horizontal component of the magnetic field). When using a map and compass, you must account for this declination. There are zones of compass unreliability as you near the magnetic north or south poles, where the compass begins to operate strangely and eventually becomes ineffective.
In addition to secular variations of the magnetic field, magnetic declination or Dip also undergoes more rapid variations due to interactions with the sun. The angle of dip is. Horizontal component of earth's magnetic field becomes zero. The magnetic poles of a freely suspended magnet will become vertical if * = B cos *
What is Magnetic Dip?
An inclination of a magnetic needle of a compass with respect to a horizontal surface
Dip is 0 at equator, 90° at poles.
Dip is not constant.
Magnetic Declination
Magnetic declination is the horizontal ∠ between True Meridian & Magnetic Meridian through the pt under consideration.
Types of Declination
Declination west (θW)
If the magnetic meridian is on the left side of the true meridian, the angle formed between the two meridians is Declination west.
Declination east (θE)
Magnetic meridians are located on the right side of true meridians. The angle formed between these meridians is Declination east.
FAQs on Angle of Dip
1. What is the angle of dip?
The angle of dip, also known as magnetic inclination, is the angle that the Earth's total magnetic field vector makes with the surface of the Earth, or the horizontal direction, in the magnetic meridian. It essentially measures how steeply the magnetic field is pointing downwards or upwards at a particular location.
2. What is the formula used to calculate the angle of dip?
The angle of dip (represented by the symbol δ) is calculated using the horizontal (BH) and vertical (BV) components of the Earth's magnetic field. The formula is:
tan δ = BV / BH
This shows that the dip angle is determined by the ratio of the vertical component to the horizontal component of the Earth's magnetic field at that point.
3. What is the value of the angle of dip at the magnetic equator and poles?
The value of the angle of dip varies significantly with location:
- At the magnetic equator, the angle of dip is 0°. Here, the Earth's magnetic field lines are parallel to the surface, meaning there is no vertical component (BV = 0).
- At the magnetic poles, the angle of dip is 90°. Here, the magnetic field lines are perpendicular to the surface, pointing straight down (at the North magnetic pole) or straight up (at the South magnetic pole), meaning the horizontal component is zero (BH = 0).
4. How is the angle of dip different from the angle of declination?
The key difference lies in the plane of measurement and what they represent:
- Angle of Dip (Inclination): This is a vertical angle. It measures the dip of the magnetic field below the horizontal plane.
- Angle of Declination: This is a horizontal angle. It measures the difference between the direction a compass points (magnetic north) and the true geographic north.
5. What are some important real-world applications of the angle of dip?
The angle of dip has several practical applications, particularly in:
- Geology and Mineral Prospecting: Geologists use local variations in the angle of dip to map subsurface rock formations and identify potential locations of magnetic ore deposits.
- Aviation and Navigation: Understanding magnetic dip is crucial for calibrating aircraft compasses. It helps pilots account for 'dip errors' that occur during turns and acceleration, ensuring accurate navigation.
6. Why is the angle of dip exactly 90° at the Earth's magnetic poles?
At the magnetic poles, the Earth's magnetic field lines are oriented vertically. They either point straight down into the Earth (at the North Magnetic Pole) or emerge straight out (at the South Magnetic Pole). Since the angle of dip measures the inclination from the horizontal, and the field at the poles is purely vertical, the angle between the horizontal plane and the field vector is 90°. At this point, the horizontal component of the magnetic field (BH) is zero.
7. Can the angle of dip have a negative value? What does it signify?
Yes, the angle of dip can be negative. By convention, the sign indicates the direction of the magnetic field's vertical component:
- A positive angle of dip is measured in the Northern Hemisphere, where the north pole of a dip needle points downwards.
- A negative angle of dip is measured in the Southern Hemisphere, where the north pole of a dip needle points upwards.
Therefore, a negative value simply signifies that you are in the Southern Hemisphere.
8. How do the horizontal (BH) and vertical (BV) components of the Earth's magnetic field influence the angle of dip?
The horizontal (BH) and vertical (BV) components are the two perpendicular parts of the Earth's total magnetic field (B). The angle of dip (δ) is the angle this total field vector makes with the horizontal. The relationship is trigonometric: tan δ = BV / BH. This means if the vertical component (BV) is large compared to the horizontal (BH), the dip angle will be high (closer to 90°), as seen near the poles. If BV is small compared to BH, the dip angle will be low (closer to 0°), as seen near the equator.
9. What would be the consequence for a magnetic compass if it were used exactly at the North Magnetic Pole?
At the North Magnetic Pole, the horizontal component of the Earth's magnetic field is zero, and the field lines point vertically downwards. A standard magnetic compass is designed to align with the horizontal component. Since this component is absent at the pole, the compass would not be able to indicate a specific direction. The needle would tend to point straight down if its movement were not restricted, making it useless for horizontal navigation.
10. If the horizontal and vertical components of the Earth's magnetic field were equal at a certain location, what would be the angle of dip?
If the horizontal component (BH) and the vertical component (BV) are equal, then the ratio BV / BH = 1. According to the formula tan δ = BV / BH, we would have tan δ = 1. The angle whose tangent is 1 is 45°. Therefore, at any location where the horizontal and vertical components of the Earth's magnetic field are equal in magnitude, the angle of dip would be exactly 45°.
