Which of the following is not the factor on which value of mutual inductance depends upon ?

Options

A. Geometry of two coils
B. Nature of the material
C. Distance between two coils
D. Electrons

Explanation

To solve the question regarding the factors on which the value of mutual inductance depends, we will analyze each option provided and determine whether it is a factor that affects mutual inductance.

### Step-by-Step Solution:

1. **Understanding Mutual Inductance**:
Mutual inductance is a property of two coils that quantifies the induced electromotive force (emf) in one coil due to a change in current in the other coil. The value of mutual inductance (M) depends on several factors.

2. **Analyzing the Options**:
- **Option 1: Geometry of the two coils**:
The geometry of the coils (such as their shape, size, and arrangement) significantly affects mutual inductance. Therefore, this is a factor that mutual inductance depends on.

- **Option 2: Nature of the material**:
The material of the coils (whether they are made of copper, aluminum, etc.) affects the magnetic permeability and thus influences mutual inductance. Hence, this is also a factor that mutual inductance depends on.

- **Option 3: Distance between the two coils**:
The distance between the coils plays a crucial role in determining the mutual inductance. As the distance increases, the mutual inductance generally decreases. Thus, this is another factor that mutual inductance depends on.

- **Option 4: Electrons**:
The term "electrons" does not directly influence the value of mutual inductance. While the flow of electrons constitutes current, the mutual inductance itself is not dependent on the number of electrons. Therefore, this is the option that does not represent a factor affecting mutual inductance.

3. **Conclusion**:
Based on the analysis of each option, the correct answer to the question "Which of the following is not the factor on which the value of mutual inductance depends upon?" is **Option 4: Electrons**.