Tyndal effect is a applicable when

          a) The diameter of the dispersed particle is not much smaller than the wavelength of the light used

          b) The diameter of the dispersed particle is much smaller than the wavelength of the light used

          c) The refractive indices of the dispersed phase and the dispersion medium must be same

          d) The refractive of the dispersed phase and the dispersion medium must differ greatly in magnitude

Not every scattering of light can be Tyndall effect. For example, when the sky is overcast, the sunlight passes through the turbid layer of the clouds, resulting in scattered and diffused light on the ground. This does not exhibit Tyndall scattering because the cloud droplets are larger than the wavelength of light and scatter all colors almost similarly. Two conditions to be satisfied to observe Tyndall effect:

• The diameter of the dispersed particles should be smaller than the wavelength of light used
• The refractive indices of dispersion medium and the dispersed phase must vary in magnitude to a large scale