A magnetic needle, perfectly balanced about a horizontal axis, is free to swing in a plane of the magnetic meridian. In its equilibrium position, the needle makes an angle 'a (alpha)' with the vertical direction at that place. What is the angle of dip at the place?
It would be simply 90o-ά as the angle of dip is defined as the angle made by the total magnetic field of the earth with the horizontal direction. As angle made with the vertical in this case is ά(alpha. Hence With horizontal direction, it would be 90-ά using complementary angle rules.
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