Question

Isogonic lines on a magnetic map will have
A. Zero angle of dip
B. Zero angle of declination
C. The same angle of dip
D. The same angle of declination

Answer 1

Hint: The word isogonic means to connect the point’s of earth’s surface which have the same magnetic declination. Angle of dip is the angle that earth’s total magnetic field makes with the direction of magnetic meridian.

Complete step by step answer:
Isogonic lines are imaginary lines around the Earth's surface along which the magnetic declination has the same value or a constant value.
On the other hand, the angle between the geographical meridian and the magnetic meridian at a place is known as magnetic declination. Magnetic declination changes over time as the angle varies depending upon the position on earth’s surface. It can also be defined as the angle on the horizontal plane between magnetic north and true north.
Furthermore, the angle that earth’s total magnetic field makes with the direction of magnetic meridian is called the angle of dip or magnetic inclination.
Therefore, the isogonal lines on a magnetic map will have a similar angle as that of magnetic declination.
Additional Information:
The straight line passing through the geographical North Pole and South Pole of earth is known as the geographic axis. It is also the axis of rotation of earth.
The magnetic declination arises because the magnetic axis of earth does not coincide with the geographical axis of earth.
At the magnetic equator, the dip needle rests horizontally so that the angle of dip is zero at the magnetic equator.

Note: The magnetic declination at any point on earth’s surface can be easily measured by the help of celestial bodies like stars, which are also used to mark the direction of true north and south. The physical instrument which is used to perform the measurement of magnetic declination is known as declinometer.