Final answer:
The emf in Faraday's law is induced around the boundary of the surface used to compute the magnetic flux(option b).
Step-by-step explanation:
The electromotive force (emf) that appears in Faraday's law is found around the boundary of the surface used to compute the magnetic flux, which makes option (b) the correct answer to the question.
According to Faraday's law of induction, an emf is induced in a circuit whenever the magnetic flux through that circuit changes. Faraday's law can be mathematically written as ε = -dφm/dt, where ε represents the induced emf, and dφm/dt is the rate of change of the magnetic flux φm through the circuit.
Faraday's law is applicable to all kinds of changes in magnetic flux, whether caused by a changing magnetic field, motion of the conductors in the field, or a combination of the two. The direction of the induced emf also satisfies Lenz's law, which states that the induced emf will create a current that opposes the change in flux that produced it, thus maintaining the originally existing flux through the surface bounded by the conductor.