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Original magnet MOS is bent at O, the mid point at 60 °. All sides are equal� The mutual interaction force between two small magnets of moments
M 1 and M 2 is given by�
F = K 6M 1 M 2 / d 4 in end- on position. Here, d denotes the separation between magnets.
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� Magnetic length = 5 / 6 * geometric length of magnet. �
� Cause of diamagnetism is orbital motion and cause of Para magnetism is spin motion of electrons. Cause of ferromagnetism lies in formation of domains. �
� The perpendicular bisector of magnetic axis is known as neutral axis of magnet. Magnetism at neutral axis is zero and at poles is maximum. �
� For steel coercivity is large. However, retentivity is comparatively smaller in case of steel. So, steel is used to make permanent magnets. �
� For soft iron, coercivity is very small and area of hysteresis loop is small. So, soft iron is an ideal material for making electromagnets. �