Phy Electromagnetic effects 2

2015-05-25 11:28 pm
Is there any magnetic field outside a solenoid if it is connected to a
a) D.C supply
b)A.C supply
??
And why ??
(if the reason is too complicated,then just let me know a simplified version)

thank you ^_^

回答 (1)

2015-05-26 1:31 am
✔ 最佳答案
In theory, both DC and AC will give rise to magnetic field outside a solenoid. But if you only refer to a steady magnetic field, then DC is the answer.

An AC current gives rise to time varying magnetic field. A compass needle will not be deflected by such time varying field. Time varying fields can be measured by means of a "search coil" connected to a sensitive galvanometer in school laboratory.


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