DYAL SINGH COLLEGE, KARNAL PHYSICS PRACTICAL

DYAL SINGH COLLEGE, KARNAL PHYSICS PRACTICAL. NAME- ISHT CHAWLA CLASS- B.SC C.S. 5 TH SEM ROLL NO -3150010027 SUBMITTED TO- MR. DEVINDER SINGH.

AIM. To find the diameter of Lycopodium Powder particles using Corona rings..

APPARATUS. A Corona plate, Glass plate, Lycodium powder, High Power microscope, Optical bench and Sodium lamp..

FORMULA USED. d= 1.22 λ D/x Where λ = wavelength of light x=Distance of given set of pin holes from the center of corona plate and D= Distance between the corona plate and glass plate..

DIAGRAM. CORONA PLATE GLASS PLATE WITH LYCOPODIUM POWDER X'.

PROCEDURE. Form a thin uniform layer of lycopodium powder by sprinkling it on the glass plate and judge it under the microscope. Mount the corona plate on an upright of the optical bench. Mount the glass formed as above on the other upright. Find the index correction between these two. The central hole of the corona plate is illuminated with sodium light. Look through the glass plate on the central hole of the corona plate. The diffraction circular fringes of yellow color will be seen. Adjust the distance of the upright containing glass plate by keeping eye close to the glass plate, so that the first dark ring coincides with the first set of pin holes at a distance x from the center of the circular hole. Note the position of two uprights..

Adjust the position of the glass plate upright so that the 1st dark ring coincides with the second set of pin holes. Again note the position of two uprights. Repeat the above observation for 3 rd set of pin holes. The distance of different set of pin holes from the center of the circular hole on the metal plate are measured with the help or travelling microscope. Find the mean value of D/x and calculate the diameter of lycopoDium powder particles by applying the given formula..

OBSERVATIONS. Mean wavelength of sodium light λ = 5893 Å = 5.893*10 -5 cm Reading of travelling microscope.

S.NO POSSITION OF UPRIGHT CARYING VALUE OF D=(a-b)(cm) x cm D/x CORONA PLATE a (cm) GLASS PLATE b (cm) OBSERVED CORRECTED 1. 36.5 cm 88.7 cm 52.2 52.1 0.51 102.15 2. 46.8 cm 97.2 cm 52.4 50.3 1.041 48.318.

PRECAUTIONS. A thin uniform layer of lycopodium powder should be formed on the glass plate. All the holes in corona plate should be illuminated with the light from the sodium lamp. The middle portion of the dark ring should be coincide with the center of holes. Index correction with its appropriate sign should be found out and applied in order to obtain correct value of D..

CALCULATIONS. d= 1.22 λ D/x= 0.0054089 cm Where λ = 5893* 10 -8 cm d= 1.22* 5.893* 10 -5 *(D/x)cm= 54.089*10 -4 cm Mean value of d= 54.08* 10 -4 cm.

RESULT. The diameter of lycopodium powder particle as determined by corona plate= 0.0054089.