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- Phenomenon seen in the elastic and
- electromagnetic behaviour of materials, in
- which a lag occurs between the application or
- removal of a force or field and its effect.
- If the magnetic field applied to a magnetic
- material is increased and then decreased back
- to its original value, the magnetic field
- inside the material does not return to its
- original value. The internal field `lags'
- behind the external field. This behaviour
- results in a loss of energy, called the
- hysteresis loss, when a sample is repeatedly
- magnetized and demagnetized. Hence the
- materials used in transformer cores and
- electromagnets should have a low hysteresis
- loss. Similar behaviour is seen in some
- materials when varying electric fields are
- applied (electric hysteresis). Elastic
- hysteresis occurs when a varying force
- repeatedly deforms an elastic material. The
- deformation produced does not completely
- disappear when the force is removed, and this
- results in energy loss on repeated
- deformations.
-