Assertion (A): The scattering of light while passing through a true solution is called Tyndall effect.
Reason (R): Intensity of scattered light is inversely proportional to the fourth power of wavelength.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is NOT the correct explanation of A
C. A is true but R is false
D. A is false and R is True

Explanation

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "The scattering of light while passing through a true solution is called Tyndall effect."

- A true solution is a homogeneous mixture where the solute particles are at the molecular or ionic level and are too small to scatter light significantly.
- The Tyndall effect, however, occurs when light is scattered by larger particles in a colloidal solution, not a true solution.

**Conclusion for Step 1**: The assertion is **false** because the Tyndall effect is not observed in true solutions.

### Step 2: Analyze the Reason
The reason states: "Intensity of scattered light is inversely proportional to the fourth power of wavelength."

- This statement is based on Rayleigh's scattering law, which indeed states that the intensity (I) of scattered light is inversely proportional to the fourth power of the wavelength (λ), expressed mathematically as:
\[ I \propto \frac{1}{\lambda^4} \]
- This means that shorter wavelengths scatter more intensely than longer wavelengths.

**Conclusion for Step 2**: The reason is **true**.

### Final Conclusion
- The assertion is **false**.
- The reason is **true**.
- Therefore, the correct answer is that the assertion is false and the reason is true.