निम्नलिखित में से कौन सी भौतिकी की शाखा नहीं है ?

Options

A. यांत्रिकी
B. प्रकाशिकी
C. साइटोजेनेटिक्स
D. विद्युत यांत्रिकी

Explanation

**Step-by-Step Solution:**

1. **Identify the Options:**
We need to analyze the given options to determine which one is not a branch of physics. The options provided are:
- A) Mechanics
- B) Optics
- C) Cytogenetics
- D) Electrodynamics

2. **Define Each Option:**
- **Mechanics:** This is the branch of physics that deals with the motion of objects and the forces acting on them. It is a fundamental area of study in physics.
- **Optics:** This branch focuses on the study of light, its properties, and its interactions with matter. It is also a well-established field within physics.
- **Cytogenetics:** This is a branch of biology that studies the structure and function of the cell, particularly the chromosomes. It is not related to physics.
- **Electrodynamics:** This area of physics deals with the study of electric charges and their interactions. It is a significant branch of physics.

3. **Determine the Non-Physics Branch:**
By analyzing the definitions:
- Mechanics, Optics, and Electrodynamics are all branches of physics.
- Cytogenetics, however, is a branch of biology.

4. **Conclusion:**
Therefore, the option that is not a branch of physics is **C) Cytogenetics**.

**Final Answer:** C) Cytogenetics

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