Question

A) Tyndall effect is observed in colloids but not in solutions.
Explain.
B) Give three examples of Tyndall effect observed around us.

[5 Marks]
[Exemplar]
[Tyndall Effect]

Answer 1

Solution:

(A)
Milk: It is a colloid. Particles are large enough (1-1000 nm) to scatter a beam of light; Hence Tyndall effect is observed.

[1 Mark]

Vinegar: It is a solution. Particles are too small (< 1 nm) and do not scatter a beam of light; Hence Tyndall effect is not observed.
[1 Mark]

(B) Three examples of Tyndall effect:

• Scattering of sunrays passing through the canopy of dense forest

[1 Mark]

• Scattering of light emitted from headlight of a car in fog

[1 Mark]

• Scattering of light emitted from lampposts on roads

[1 Mark]