'The induced emf and current persist as long as the magnetic flux is changing. This is the statement for

Options

A. Faraday's second law
B. Lenz's law
C. Faraday's first law
D. Laplace's law

Explanation

To solve the question regarding the statement about induced emf and current, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding Induced EMF and Current**: The statement mentions that "the induced emf and current persist as long as the magnetic flux is changing." This refers to the phenomenon of electromagnetic induction, where a change in magnetic flux through a circuit induces an electromotive force (emf) and consequently a current.

2. **Faraday's Law of Electromagnetic Induction**: This principle is encapsulated in Faraday's Law, which states that the induced emf in a closed loop is directly proportional to the rate of change of magnetic flux through the loop. Mathematically, it is expressed as:
\[ E = -\frac{d\Phi}{dt} \]
where \(E\) is the induced emf, \(\Phi\) is the magnetic flux, and \(t\) is time.

3. **Direction of Induced Current**: The negative sign in Faraday's Law indicates that the direction of the induced emf (and hence the current) opposes the change in magnetic flux that produced it. This is known as Lenz's Law.

4. **Conservation of Energy**: The principle underlying this phenomenon is the conservation of energy, which states that energy cannot be created or destroyed. The induced current creates a magnetic field that opposes the change in the original magnetic field, thus conserving energy in the system.

5. **Conclusion**: Therefore, the statement "The induced emf and current persist as long as the magnetic flux is changing" is a direct reference to Faraday's Law of Electromagnetic Induction and Lenz's Law.

### Final Answer:
The statement refers to **Faraday's Law of Electromagnetic Induction**.