Question

Tyndall effect is produced by:

• A. True solutions of light
• B. Scattering of light
• C. Refraction of light
• D. Movement of particles

Hint:

The Tyndall effect is a result of the scattering of light by particles in colloidal solutions, not by their movement or refraction.

Answer 1

The Correct Option is B

Understanding the Concept:
When a beam of light travels through a colloid, an observer looking from the side can see the path of the beam glowing, rather than the beam staying invisible the way it would in clean air or a true solution.

Key Formula or Approach:
Light can interact with matter in a few distinct ways: it can bend at a boundary between two media (refraction), bounce off a surface at a definite angle (reflection), or get redirected in many directions by small particles in its path (scattering).

Detailed Explanation:
In a colloid, tiny particles of sizes comparable to the light's wavelength sit scattered through the medium. As the beam passes each particle, some of that light gets thrown off sideways, forward, and backward in many directions rather than continuing in a single straight line. It is this redirection in many directions, not a single bend at one boundary, that lets an observer see the beam glowing from angles well away from the original direction of travel. That process is called scattering, and it is what makes the Tyndall effect visible.

Final Answer:
The Tyndall effect is produced by the scattering of light.

Answer 2

Another way to settle this is to check what each listed phrase actually refers to in physics, and see whether that definition matches what is observed in the Tyndall effect (a glowing beam visible from the side).

1. True solutions of light: This is not a standard physical process; true solutions are, if anything, the case where this effect does not occur, since their particles are too small to interact with light this way.
2. Scattering of light: Scattering is defined as light being redirected in many directions after striking particles roughly its own wavelength in size, exactly the mechanism that makes a beam visible from the side in a colloid.
3. Refraction of light: Refraction is strictly about a beam bending as it crosses into a different medium at one boundary; it does not describe a beam being deflected sideways at many points along its path inside one medium.
4. Movement of particles: This describes the particles' own motion (as in Brownian motion), a mechanical effect, not an optical one, and it does not by itself explain why light becomes visible from the side.

Matching each phrase to its real physical meaning, only scattering describes light being redirected by particles in many directions, which is what the Tyndall effect actually shows.

So the correct answer is scattering of light.