Concept:Hysteresis error occurs because magnetic flux density (
B) lags behind the magnetizing current, so
B differs for the same current value while increasing versus decreasing.
Explanation:In magnetic instruments, when the current is gradually increased, the flux density follows one path, and when the current is decreased, it follows a different path.
For the same value of current, the flux density is different during increasing and decreasing cycles, producing the hysteresis error.
This lag happens because magnetic domains resist changes in their alignment, a property known as hysteresis.
The hysteresis loop, also called the B-H curve, represents this relationship graphically.
The area of this loop gives the energy loss per cycle, expressed as
Wh​=∮BdH per unit volume of the magnetic material.
Frequency relates to cycles per second and is measured in Hertz (
Hz), so it is not the correct answer.
Friction opposes mechanical motion between surfaces and is irrelevant to magnetic flux density behaviour.
Temperature affects resistance and thermal expansion but does not cause this specific error.
Hence, the blank is correctly filled by hysteresis.
Answer:Option A: Hysteresis