in which of the followings, effect is / are not observed ?

Options

A. sugar solution
B. emulsion
C. Urea solution
D. solution of proteins

Answer

To determine in which of the following cases the Tyndall effect is not observed, we need to understand the nature of the solutions mentioned.

### Step-by-Step Solution:

1. **Understanding Tyndall Effect**:
- The Tyndall effect is the scattering of light by particles in a colloid or particles in a very fine suspension. It is observed when a beam of light passes through a colloidal solution, causing the light to scatter and become visible.

2. **Identifying Colloids**:
- Colloids are mixtures where one substance is dispersed evenly throughout another. Examples include emulsions (like milk), fog, smoke, and gels. These substances contain suspended particles that can scatter light.

3. **Analyzing the Given Solutions**:
- **Sugar Solution**: This is a clear solution formed when sugar is dissolved in water. It does not contain any suspended particles; hence, it does not exhibit the Tyndall effect.
- **Urea Solution**: Similar to the sugar solution, urea dissolved in water also forms a clear solution without suspended particles, and thus it also does not show the Tyndall effect.

4. **Conclusion**:
- Since both sugar solution and urea solution are clear and do not contain colloidal particles, the Tyndall effect is not observed in either of these solutions.

### Final Answer:
The Tyndall effect is not observed in sugar solution and urea solution.

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