Spectrometer - Goniometer

Spectrometer-Goniometer is a versatile instrument for studying the spectrum of different light sources as well as for characterization of components like prisms and gratings. Unlike common spectrometers, this model is designed in such a way that students get better understanding of the working principles of spectrometer. All modules are deliberately made open and easy to understand. Students gain hands on experience in the basics of spectroscopy.

This Goniometer is used for measuring optical data of prisms. It offers precise angle and refractive index measurements. The well designed mechanics of the Goniometer allows maintenance-free operation over many years. Conventionally, the measurement of refractive index is carried out with a dispersion prism made from the material to be tested. For the measurement of refractive index of fluids, a hollow prism, which is filled with the liquid, is used. It can also be used as a spectroscope for qualitative examination and measurement of emission and absorption spectra.

Experiment

   To determine the focal length of convex lens.

The refractive index of the solid prism using the formula,

n    =    sin  ( (α+β) / 2 )   /   sin (α/2)

Where α is angle of the prism & β is angle of minimum deviation.

   Refractive index of various liquids using liquid prism.

If a parallel beam of monochromatic light is incident normally on the face of a plane transmission diffraction grating, bright diffraction maxima are observed on the other side of the grating. These diffraction maxima satisfy the grating condition :

d sinθ = nλ

d is the distance between slits = 1/N is the grating constant, is the number of lines per unit length. n is the order of spectrum which can take values 0, ±1, ±2, ±3 …….

λ is the wavelength of the incident light.

This equation is referred to as grating equation.

Specifications:

Inspection Telescope Magnification	10 x
Resolution of Prism Table	30 arc minute
Resolution of Stage	1 arc minute
Variable slit	Micrometer controlled, continuously variable 0 - 3mm

Features:

Modern and user friendly design

Mercury lamp is used as light source

Symmetrical precision slit

Height of prism table is adjustable

High-quality optics

Drawings:

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