A line passing through points on the Earth's surface where the magnetic declination is zero is known as a/an ___________.

Consider the following statements: Statement I: The Earth's magnetic field is sustained by dynamic processes operating in its fluid outer core, rather than by the Earth behaving as a permanent bar magnet. Statement II: The motion of electrically conducting material in the outer core is fundamental to the generation and maintenance of the geomagnetic field. Which one of the following is correct in respect of the above statements?

The vertical component of Earth's magnetic field at a place is 1√3 times the horizontal component. The angle of dip at that place is: