A piece of magnetized steel used as an indicator on the dial of a compass and in magnetic and electrical apparatus.
Example sentencesExamples
- In 1837 Cooke and Wheatstone developed the electric telegraph which used an electric current to move magnetic needles and thus transmit messages in code.
- In particular he carried out many experiments including some on ballistics, some on the pendulum and a study of the variation of the magnetic needle.
- A 14 mm wide channel formed by two glass plates was made along the axis of the magnetic gradient within which a magnetic needle (a Teflon rod 3 cm long and 2 mm diameter) was floated.