Which of the following satements is not correct?

Options

A. whenever the amount of magnetic flux linked with a circuit change, an emf is induced in the circuit.
B. The induced emf so long as the change in magnetic flux continues.
C. The direction of induced emf is give by Lenz's law.
D. Lenz's law is a consequence of the law of conservation of momentum.

Answer

To determine which statement is not correct regarding electromagnetic induction, we will analyze each statement one by one based on the principles of Faraday's law and Lenz's law.

### Step-by-Step Solution:

1. **Statement 1: Whenever the amount of magnetic flux linked with the circuit changes, EMF is induced in the circuit.**
- According to Faraday's law of electromagnetic induction, a change in magnetic flux through a circuit induces an electromotive force (EMF) in that circuit. This statement is correct.

2. **Statement 2: The induced EMF exists so long as the change in magnetic flux continues.**
- This statement is also true. The induced EMF is directly related to the rate of change of magnetic flux. If the change in magnetic flux stops, the induced EMF will also cease to exist.

3. **Statement 3: The direction of induced EMF is given by Lenz's law.**
- Lenz's law states that the direction of the induced EMF will be such that it opposes the change in magnetic flux that produced it. This statement is correct.

4. **Statement 4: Lenz's law is a consequence of the law of conservation of momentum.**
- This statement is incorrect. Lenz's law is actually a consequence of the law of conservation of energy, not momentum. The induced EMF opposes the change in magnetic flux, which requires work to maintain the change, and this work is converted into electrical energy.

### Conclusion:
The statement that is not correct is **Statement 4**: "Lenz's law is a consequence of the law of conservation of momentum."

### Final Answer:
The correct answer for the above question is **Option B**.

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