What is induced voltage primarily caused by?

Induced voltage is primarily caused by changes in magnetic fields. This phenomenon is described by Faraday's law of electromagnetic induction, which states that a change in magnetic flux through a circuit induces an electromotive force (EMF) in that circuit. When the magnetic field around a conductor changes, whether by moving the conductor through a stationary magnetic field or by changing the strength of the magnetic field itself, a voltage is induced in the conductor.

This concept is fundamental in applications such as generators and transformers, where mechanical motion or varying magnetic fields are utilized to produce electricity. The induced voltage is directly proportional to the rate at which the magnetic field changes, which is why magnetic field changes are the correct cause of induced voltage.

Other options, while related to electrical concepts, do not directly lead to induced voltage. Electrostatic charge is static and does not cause voltage induction. Resistance in a circuit relates to how much current flows in response to an applied voltage, but it does not cause voltage to be induced. Static electricity is another form of electrical charge that does not involve the dynamic changes in magnetic fields necessary for inducing voltage.