Question

Expression for the resolving power of prism

Answer 1

Answer:

R = b · dn

Explanation:

where b is the base of the prism. Resolving power R is determined in the 'yellow' and the 'blue' regions of the spectrum from the slope of the disper- sion curve

Answer 2

Explanation:

Maxwell relationship, dispersion, polarizability, refractive in-

dex, prism, Rowland grating, spectrometer-goniometer.

Principle and task

The refractive indices of liquids, crown glass and flint glass are

determined as a function of the wavelength by refraction of

light through the prism at minimum deviation. The resolving

power of the glass prisms is determined from the dispersion

curve.

Equipment

Spectrometer/goniom. w. vernier 35635.02 1

Lamp holder, pico 9, f. spectr.lamps 08119.00 1

Spectral lamp Hg 100, pico 9 base 08120.14 1

Power supply for spectral lamps 13662.93 1

Prism, 60 degrees, h 30 mm, crown 08231.00 1

Hollow prism 08240.00 1

Diffraction grating, 600 lines/mm 08546.00 1

Glycerol 250 ml 30084.25 1

Methanol 500 ml 30142.50 1

Cyclohexene for synth. 500 ml 31236.50 1

Wash bottle, plastic 250 ml 33930.00 1

Bench clamp, -PASS- 02010.00 1

Stand tube 02060.00 1

Problems

1. To adjust the spectrometer-goniometer.

2. To determine the refractive index of various liquids in a hol-

low prism.

3. To determine the refractive index of various glass prism.

4. To determine the wavelengths of the mercury spectral lines.

5. To demonstrate the relationship between refractive index

and wavelength (dispersion curve).

6. To calculate the resolving power of the glass prisms from

the slope of the dispersion curves.

Set-up and procedure

The experiment is set up as shown in Fig. 1.

The spectrometer-goniometer and the grating should be ad-

justed in accordance with the operating instructions. When the

adjustment is correct, a parallel beam of light will pass through

the prism (Fig. 2).

The aperture, or slit, is projected into the plane of the cross-

wires with the telescope set to infinity and observed with the

eyepiece which is used as a magnifier.

The prism is then set to the minimum deviation and the angu-

lar position f1 of the telescope read off on the vernier for each

R

Fig. 1: Experimental set-up for determining dispersion in liquids.