Particle Size Measurement

Item Code: SK172

Working and Principle :

Shine an expended He-Ne laser beam through a plate dusted with lycopodium powder to construct circular rings on the screen which are nearly spherical and have a very uniform average diameter. The quality of the ring depends on the evenness of lycopodium powder.

... Wavelength of given laser source ʎ=sin⁡θ/Nn
N = No. of lines per meter of grating
Grain size (diameter) ‘2d’ of the grain
2d = nʎD/Xn
Where
n - Order of diffraction
l - Wavelength of laser used in meter
D - Distance between glass plate and screen in meter
Xn- Distance between central bright spot and the nth fringe in meter




  • Supplied with 3 in 1 grading (100,300,600 lines per mm)
  • He-Ne laser with in-built power supply.
  • Translucent screen to view the diffraction pattern.
  • Saddle can hold rod from 8 to 15mm.
  • Heavy, rigid and stable Triangular Optical bench (made of Al extrusion).
  • Height and level adjustment screws (made of SS)

  • Determination the wavelength of He-Ne laser using diffraction grating.
  • Determination the particle size of lycopodium powder.
  • Optical bench : Al exclusion, L = 1m, Triangular shape with end stop, 4 point levelling (SS screw)
  • Fixed slider : Al Extrusion, Base W x H,50mm x 115mm
  • Screen : Acrylic(translucent) 300 x 300 x 3mm
  • Laser : He-Ne Laser (632mm), Power 2 mW, Beam spot 2.5mm, current 4mA ~ 6mA, Dimension 300 x 62 x 82mm
  • Diffraction Grating : Size 89 X 38 mm, Aperture 16 X 9 mm Rulings 100,300,600 lines/mm
  • Lycopodium Powder: 50 gm
  • Slit Holder : Aperture 45x45mm, Clip type holder Mounting rod 10mm
  • 1 He-Ne laser
  • 1 Optical Bench triangular
  • 1 Object screen
  • 2 Glass plate (40 x 40mm)
  • 1 Diffraction grating (imported)
  • 1 Slit holder
  • 1 Slit (Blade)
  • 1 Measuring tape (3 m)
  • 1 Lycopodium powder
  • 2 Fixed slider
  • 1 Fixed slider large width
  • Diffraction.
  • Fresnel diffraction.
  • Fraunhofer diffraction
  • Uncertainty of location.
  • Wave-particale.