Spectrometer-Goniometer (Model No. HO-ED-S-01) 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 fluid is used. It can also be used as a spectroscope for qualitative examination and measurement of emission and absorption spectra.
The refractive index of the solid prism using the formula,
n = sin ( (α+β) / 2 ) / sin (α/2)
ω = (n2- n1) / (n - 1)
n1 and n2 are the refractive indices of the prism for any two colours, and n = (n1 + n2 ) / 2
Replace the solid prism with hollow prism containing the liquid for which the refractive index to be calculated.
The experimental procedure is same as solid 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:
N sin qn = nl
Where N is the the number of rulings in grating,
qn is the angle of diffraction of the nth maximum.
n is the order of spectrum which can take values 0, ±1, ±2, ±3 …….
l is the wavelength of the incident light.