Define the terms 'Magnetic Dip' and 'Magnetic Declination' with the help of relevant diagrams.
Solution
Magnetic dip (inclination) δ at a place is the angle that the direction of Earth's total magnetic field B makes with the horizontal plane. A dip needle free to rotate in the vertical magnetic meridian settles at this angle. Magnetic declination θ at a place is the angle between the geographic meridian (vertical plane through geographic N-S) and the magnetic meridian (vertical plane through the freely suspended needle). Together with the horizontal component BH, these are the elements that fix Earth's field at a place.