Question

short note on tyndall effect

Answer 1

The Tyndall effect, also known as Tyndall scattering, is light scattering by particles in a colloid or else particles in a very fine suspension. It is named after the 19th-century physicist John Tyndall. It is similar to Rayleigh scattering, in that the intensity of the scattered light depends on the fourth power of the frequency, so blue light is scattered much more strongly than red light. An example in everyday life is the blue colour sometimes seen in the smoke emitted by motorcycles, in particular two-stroke machines where the burnt engine oil provides the particles. Under the Tyndall effect, the longer-wavelength light is more transmitted while the shorter-wavelength light is more reflected via scattering. An analogy to this wavelength dependency is that longwave electromagnetic waves such as radio waves are able to pass through the walls of buildings, while shortwave electromagnetic waves such as light waves are stopped and reflected by the walls. The Tyndall effect is seen when light-scattering particulate-matter is dispersed in an otherwise-light-transmitting medium, when the cross-section of an individual particulate is the range of roughly between 40 and 900 nanometers, i.e., somewhat below or near the wavelength of visible light (400–750 nanometers). It is particularly applicable to colloidal mixtures and fine suspensions; for example, the Tyndall effect is used commercially to determine the size and density of particles in aerosols and other colloidal matter (see ultramicroscope and turbidimeter).

Answer 2

Answer:

The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible. The Tyndall effect was first described by 19th-century physicist John Tyndall.The amount of scattering depends on the frequency of the light and density of the particles. As with Rayleigh scattering, blue light is scattered more strongly than red light by the Tyndall effect. Another way to look at it is that longer wavelength light is transmitted, while shorter-wavelength light is reflected by scattering.

The size of the particles is what distinguishes a colloid from a true solution. For a mixture to be a colloid, the particles must be in the range of 1-1000 nanometers in diameter.