It is due to the law of inductance: V = L di/dt which says if there is no change in current over time than the induced Voltage will be zero. So DC will not induce anything and will not see any DC Voltage from inductance. Also have a look on WIKI.
Because a current is only induced in a conductor by a changing magnetic field. Only a changing current can produce a changing magnetic field (in stationary conductors). Now, technically, a DC current _can_ create a changing magnetic field if that DC current is changing in _magnitude_ but not _polarity_--e.g. from a positive current to a more, or less, positive current OR from a negative current to a more, or less, negative current (if you consider "AC" to mean a current that "Alternates" between positive and negative).
Wow Earl can you feel empathy? Even if it is a beginner question it is NOT a stupid question. Would you have liked that answer when you were learning electronics?
Induced current is always alternating current (AC) rather than direct current (DC) because it arises from a changing magnetic field, which requires a time-varying current or magnetic flux. According to the law of inductance (V = L di/dt), if the current does not change over time (as in steady DC), the induced voltage and thus induced current will be zero. A DC current can only induce a current if its magnitude changes over time, but not if it remains constant. This principle is rooted in Faraday's law of electromagnetic induction and Lenz's law, which state that only a varying magnetic field can induce an electromotive force (EMF) and consequently an induced current in a conductor. Summary generated by the language model.
