Final answer:
When a magnetic field goes through a loop, an electric current is induced due to Faraday's law of induction. The direction of the induced current is determined by Lenz's law.
Step-by-step explanation:
When a magnetic field goes through a loop, an electric current is induced. This is due to Faraday's law of induction, which states that a changing magnetic flux through a conducting loop will create an induced emf (electromotive force) and consequently an electric current. The direction of the induced current is determined by Lenz's law, which states that the induced current flows in a direction that opposes the change that caused it.