Magnetic Field of Earth: Sir William Gilbert was the first to suggest that the earth itself is a huge magnet. His statement was based on the following evidence- A magnet suspended from a thread comes to rest along the North-South direction. This is as if a huge fictitious magnet is buried along the diameter of the earth. The North pole of this fictitious magnet must be towards the geographic South, so as to attract the South Pole of the suspended magnet and vice versa. When a soft iron core is buried under the earth in the North-South direction, it is … Continue reading Magnetic Field of Earth