Which of the following does not depict the correct link between technology and physics ?

Options

A. Photocell - Photoelectric effect
B. Rocket propulsion - Laws of thermodynamics
C. Optical fibres - Total internal reflection of light
D. Fusion test reactor - Magnetic confinement of plasma

Explanation

To solve the question of which option does not depict the correct link between technology and physics, we can analyze each option provided.

1. **Photocell and Photoelectric Effect**:
- The photoelectric effect is a physics concept that explains how light can eject electrons from a material. The photocell, which utilizes this effect to convert light into electricity, is a technological application of this concept. This link is correct.

2. **Rocket and Propulsion**:
- Rocket propulsion is based on Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. While rocket technology utilizes this principle, the law of thermodynamics does not directly explain rocket propulsion. Therefore, this link is incorrect.

3. **Optical Fiber and Total Internal Reflection**:
- Total internal reflection is a physics concept that describes how light behaves when it hits a boundary at a certain angle. Optical fibers utilize this principle to transmit light over long distances. This link is correct.

4. **Fusion and Test Reactor**:
- Fusion is a process that combines light atomic nuclei to form heavier nuclei, releasing energy. Test reactors are technological devices designed to study and harness this process. This link is correct.

5. **Magnetic Confinement of Plasma**:
- This technique is used in fusion reactors to contain hot plasma using magnetic fields. This is a technological application based on physics principles. This link is correct.

After analyzing all the options, we conclude that the link between **rocket propulsion and the law of thermodynamics** does not accurately depict the relationship between technology and physics.

### Final Answer:
The option that does not depict the correct link between technology and physics is **rocket propulsion and law of thermodynamics**.