Spectrometry kit

Item Code: SK001

Principle and Working:

The working of a spectrometer is based on the principle that when light falls on an optical device such as a prism or diffraction grating each wavelength is refracted or bent by a unique angle. A precise spectrum can be determined by measuring the angles at which light is refracted or bent.




  • Main scale & Vernier scale are made of Brass on CNC machine.
  • Two Vernier used to remove eccentric error.
  • Least count 1 min. for measuremen.
  • Highly stable spectrometer body (weight 6 kg approx.).
  • Supplied in black wooden box.
  • Adjustable optical arms to coincide axis of collimeter & telescope.
  • Optics aperture 32 mm for better resolution.

Learning Objectives/experiments

  • To determine the dispersion & resolving power of the prism.
  • To determine the wavelength of sodium light & also determine resolving power of using a diffraction grating.
  • To determine angular dispersive by grating or prism.
  • To determine the refractive index of prism.
  • To determine wavelength of mercury spectral lines (optional).
  • To verify Cauchy’s equation (using Mercury light source).To draw graph
    (i) between wavelength ( λ) and minimum 2derivation angle.
    (ii) between 1/ λ and minimum angle for prism for various lines from the spectrum of mercury discharge source.
  • Main scale : Brass, dia. 150mm, 0 – 360 ,1 MSD ½
  • Least count : 1 minute
  • Objective : Achromatic lens, F = 178mm, Ø 32mm
  • Slit : Brass with knurled screw
  • Reticle : 90 cross etched on glass, Ø 21mm
  • Eyepiece : 15X, Ramsdens, 22 x 23mm (LxØ)
  • Vernier : Brass, 2 verniers (for optical arms) L = 40mm
  • Base : 175mm dia., Aluminum casting
  • Prism : Arms (32 x 32 x 32mm), Height 32mm, Refractive Index 1.65
  • Micrometer slit : Range 0 – 3mm, LC 0.01mm
  • Wooden box : 400 x 320 x 315mm
  • Lamp house : MS, 200 x 85mm (LxØ), Aperture (LxW) 20 x 16mm
  • Grating : 50 x 38mm, 15,000 lines/ inch
  • 1 Intermediate spectrometer
  • 1 Sodium light source
  • 1 Prism
  • 1 Diffraction grating
  • 1 Micrometer slit
  • 1 Eye Magnifier
  • 1 Spectrometer wooden box
  • 1 Mercury light source (Optional)
  • 1 Allen key