Question

Read the following passage carefully and answer the questions that follow it

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 figure. 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 1

Answer: ANS 1.- Since milk is a colloid and when light is scattered from the particles of colloids it is illuminated and it is because of Tyndall effect. In the tyndall effect light is scattered by particles in a colloid or particles in a fine suspension while showing no light in a true solution.It is used to determine whether a mixture is true or colloidal.

Explanation: