Manetic flux through a coil is changes with respect to time then emf induced in it which incorrect regarding induced emf in coil :-

Options

A. Coil may be made up with wood
B. Coil may be connected with an open circuit
C. Coil must be of conducting nature
D. Induced emf does not depends upon resistance of the coil

Answer

To solve the question regarding induced EMF in a coil when the magnetic flux changes with respect to time, we need to analyze the statements provided and identify which one is incorrect. Let's break down the solution step by step.

### Step-by-Step Solution:

1. **Understanding Induced EMF**:
The induced EMF (Electromotive Force) in a coil is given by Faraday's law of electromagnetic induction, which states that the induced EMF is equal to the negative rate of change of magnetic flux through the coil.
\[ \text{EMF} = -\frac{d\Phi}{dt} \]
where \(\Phi\) is the magnetic flux.

2. **Magnetic Flux**:
Magnetic flux (\(\Phi\)) through a coil is defined as:
\[ \Phi = B \cdot A \cdot \cos(\theta) \]
where:
- \(B\) = magnetic field strength,
- \(A\) = area of the coil,
- \(\theta\) = angle between the magnetic field and the normal to the surface of the coil.

3. **Analyzing the Statements**:
We need to evaluate the correctness of the statements regarding the nature of the coil and its effect on induced EMF:
- **Statement 1**: "The coil may be made of wood."
- This is true. Wood is an insulator and does not conduct electricity, but it can still have a changing magnetic flux through it.
- **Statement 2**: "The coil must be of conducting nature."
- This is true. For an EMF to be induced, the coil must be made of a conducting material to allow current to flow.
- **Statement 3**: "The flux does not depend on the nature of the induced EMF."
- This statement is misleading. The nature of the induced EMF (whether it is positive or negative) does not affect the calculation of the magnetic flux itself, but the induced EMF does depend on the change in magnetic flux, which is influenced by the material properties of the coil.

4. **Identifying the Incorrect Statement**:
The statement that is incorrect regarding induced EMF in the coil is **Statement 3**. While the flux itself does not depend on the nature of the induced EMF, the induced EMF is fundamentally related to the change in that flux and the properties of the coil.

### Conclusion:
The incorrect statement regarding induced EMF in the coil is that "the flux does not depend on the nature of the induced EMF."