Mitali Konwar
The present work describes the nature of Brownian movement exhibited by colloidal suspensions. In the experiment we have used 5mW He-Ne laser light at 6328Å and also Ar+ laser light (green) to illuminate a sample cell containing the liquid with colloidal suspensions of medicinal plants Alpine allughas, Murraya Koenigii(Linn), leucas cephalotes .The intensity fluctuations of the Brownian movements are measured with the help of silicon photodiodes placed at particular positions and connected to a sensitive digital multimeter. The readings are recorded with the help of a video camera [Model DCR-TRV 460 E Sony].The records of the fluctuations are taken for about two minutes and are transferred to a computer by USB cable. The fluctuating patterns per second are worked out with the help of a computer and they indicate the nature of particular colloidal suspensions. The intensity fluctuating patterns per second also exhibit the time dependence of the random force Fv(t) which are characteristics of Brownian motion.
