If a strong beam of light is passed through a colloidal sol place in a dark space, the part of the beam gets illuminated. This phenomenon is called

Options

A. Tyndall effect
B. Brownian effect
C. Dorn effect
D. Hardy-Schulze effect

Answer

A

Explanation

If a homogeneous solution placed in dark is observed in the direction of light, it appears cler (i.e. we are able to trace out the path of light). But if it is observed from a direction at right angles to the direction of light beam, it appears perfectly dark,
Colloidal solutions viewed is the same way also appear reasonbly clear or translucent by the transmitted light but they show a mild to strong opalescence, which viewed at right angles to the passage of light i.e. the path of the beam is illuminated by a coloured light. This effect was first observed by Faraday and later studied in detail by Tyndall and is therefore termed as Faraday-Tyndall effect or just Tyndall effect, The illuminated path of beam (the bright cone of the light) is called Tyndall cone.