Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: The diameter of colloidal particles in solution should not be much smaller than wavelength of light to show Tyndall effect. 
Reason R : The light scatters in all directions when the size of particles is large enough. 
In the light of the above statements, choose the correct answer from the options given below

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

Answer 1

The Correct Option is A

The Tyndall effect is observed only when the following two conditions are satisfied: 

1. The diameter of the dispersed particles is not much smaller than the wavelength of the light used. If the particles are much smaller than the wavelength of light, scattering is negligible, and the Tyndall effect is not observed. 

2. The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude. Explanation of Statements: Assertion A: This is correct because the particle size needs to be comparable to the wavelength of light to scatter light effectively and show the Tyndall effect. Reason R: This is correct because light scatters in all directions when the particle size is large enough to cause significant scattering. Furthermore, the reason directly explains why the assertion is true. 

Conclusion: Both Assertion A and Reason R are correct, and Reason R is the correct explanation of Assertion A.