Magnetic induction can establish a difference of potential in which of the following scenarios?

Magnetic induction establishes a difference of potential through the principle of electromagnetic induction, which occurs when a conductor moves through a magnetic field or when the magnetic field around a conductor changes. This interaction induces an electromotive force (EMF) in the conductor, leading to a potential difference across it.

In this context, when conductors cut across magnetic field lines, the changing magnetic flux linked with the conductor generates a voltage. This is the fundamental principle behind devices like generators, where mechanical motion is converted into electrical energy through the act of cutting magnetic fields.

The other scenarios do not effectively illustrate the process of magnetic induction. Reducing the size of a wire may affect resistance but does not inherently create a potential difference through induction. Storing electrical energy in batteries involves electrochemical processes rather than magnetic induction. Likewise, converting light into electrical energy is a principle related to photovoltaic effects rather than magnetic induction. Therefore, the scenario involving conductors cutting through a magnetic field correctly identifies the mechanism by which magnetic induction can establish a difference of potential.