Q. 374.0( 6 Votes )

A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the Fig.2.4. They were amazed to see that milk taken in the tumbler was



illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?

(a) Explain why the milk sample was illuminated. Name the phenomenon involved.

(b) Same results were not observed with a salt solution. Explain.

(c) Can you suggest two more solutions which would show the same effect as shown by the milk solution?

Answer :

(a) The milk sample was illuminated because milk is a colloidal solution and its particles are big and hence, scatter the light passing through it. The phenomenon observed is called the “Tyndall effect” or “Tyndall scattering”.

(b) As the salt solution is a true solution i.e., the solute particle size is too small and hence they cannot scatter the light. That is why the salt solution does not show “Tyndall effect”.

(c) Examples of colloid are gold sol (colloidal gold), arsenic sulphide (AS2S3) sol, blood, detergent solution and sulphur solution. Sols have good stability and show the Tyndall effect.


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
More on Mixture & SolutionMore on Mixture & SolutionMore on Mixture & Solution31 mins
Separation of mixtureSeparation of mixtureSeparation of mixture34 mins
Champ Quiz | About Colloidal SolutionChamp Quiz | About Colloidal SolutionChamp Quiz | About Colloidal Solution30 mins
How to Distinguish Between Suspensions and Colloids??How to Distinguish Between Suspensions and Colloids??How to Distinguish Between Suspensions and Colloids??25 mins
Genius Quiz | Test Your Knowledge on Separation TechniquesGenius Quiz | Test Your Knowledge on Separation TechniquesGenius Quiz | Test Your Knowledge on Separation Techniques38 mins
Mixture & SolutionMixture & SolutionMixture & Solution38 mins
Are Elements and Compounds Types of Molecules?Are Elements and Compounds Types of Molecules?Are Elements and Compounds Types of Molecules?34 mins
Learn 5 Solid-liquid Mixture Separation Techniques!Learn 5 Solid-liquid Mixture Separation Techniques!Learn 5 Solid-liquid Mixture Separation Techniques!36 mins
Master NCERT Activities and Questions Based on ThemMaster NCERT Activities and Questions Based on ThemMaster NCERT Activities and Questions Based on Them47 mins
NCERT Exemplar | Is Matter Around Us PureNCERT Exemplar | Is Matter Around Us PureNCERT Exemplar | Is Matter Around Us Pure53 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses