This spectroscope with a set of spectral lamps is intended for the physics classrooms of educational institutions: with it students observe continuous and line spectra with their own eyes and establish the wavelengths of the radiation of gases while studying the topic of optics. Looking into the eyepiece at the spectrum of one of the lamps of the set, the student matches the visible line against a division of the built-in scale and immediately obtains the value of the wavelength without performing any additional calculations. The equipment is used in physics lessons and during practical and laboratory work in classrooms of the natural science profile; work with the lamps of the set is organised by the teacher, students observe the spectra only under direct supervision, and the recommended age of learners is from 10 years, that is pupils of grade 5 and above.
The optical system of the instrument decomposes light into a spectrum: the beam from the switched-on lamp falls on a narrow entrance slit and then on the dispersing element, and the observer sees in the eyepiece the resulting spectrum next to the scale of wavelengths and reads off the value of the line required. The spectroscope is one of direct reading with a built-in wavelength scale, it is fixed on a stable metal base 140 mm in diameter and the overall height of the construction is 220 mm. The current for the installed lamp is supplied by the power unit of the set, which excites in the lamp the electric discharge that creates the observed spectrum; the lamps are powered from an alternating current mains of 220 to 230 V at a frequency of 50 Hz through that power unit. The set contains 6 spectral lamps filled with helium, neon, hydrogen, mercury, argon and krypton, and both continuous and line spectra can be observed. Marking and operating documentation are in Ukrainian, the marking carries the trade mark, the model and a place for the inventory number, and the documentation comprises the passport with the warranty coupon and the operating instructions. The instrument is installed on a flat horizontal surface of a table and is supplied ready for work, requiring no additional assembly or alignment. Operating conditions are the premises of an educational institution at an air temperature from +5 to +40 °C and relative humidity from 40 to 60 % without condensate. The service life is 5 years and the warranty period is 12 months from the date of sale.
The set includes the direct reading spectroscope with the built-in wavelength scale on a metal base — 1 pc; the set of spectral lamps, namely helium, neon, hydrogen, mercury, argon and krypton — 6 pcs; the power unit for the spectral lamps — 1 pc; the power cable — 1 pc; the passport with the warranty coupon — 1 pc; and individual packaging — 1 pc. A source of a continuous spectrum for comparative observations, for example an incandescent lamp, is not part of the set and is provided by the educational institution itself.
In preparation the spectroscope is placed on a horizontal stable table surface protected from direct sunlight and draughts, the external surfaces are wiped with a soft dry cloth, the lamp is chosen according to the topic of the lesson and carefully installed in the holder of the power unit while being held by its base, and the mains voltage is checked against the value given in the passport and on the power unit. The spectroscope is then positioned so that its entrance slit is directed at the switched-on spectral lamp at a distance that gives sufficient brightness of the spectrum in the eyepiece. Looking into the eyepiece, the observer finds the image of the spectral lines and the wavelength scale aligned with them; each bright line corresponds to a definite wavelength of the radiation of the gas in the lamp, which is read directly off the scale in nanometres and, if needed, compared with reference data for that gas. For a continuous spectrum an external source of white light, for example an incandescent lamp, is directed at the entrance slit instead of a spectral lamp. Observations are best made in a darkened room. At the end of the work the power unit is switched off, the lamp is allowed to cool without touching its bulb with bare hands, it is taken out of the holder by its base and returned to its place in the packaging, and the external surfaces of the instrument are wiped with a dry cloth.
The set contains a lamp filled with mercury vapour. Its bulb is checked for integrity before every use and a lamp with a crack, a chip or a broken seal must not be used; if a mercury lamp breaks, the power unit is switched off at once, the students are led out of the room and the classroom is thoroughly aired, and the glass and the mercury residues are never collected with bare hands, a broom or a vacuum cleaner but with personal protective equipment and a special demercurisation kit, students being kept away from the place until the demercurisation is complete. A spent or damaged mercury lamp is not thrown out with household waste but handed over as a mercury-containing waste to a specialised organisation holding the appropriate permit. The other lamps heat up during work and are not touched with bare hands immediately after switching off, the power cable is checked for serviceability before switching on, and moisture must not reach the power unit, the lamp or the electrical contacts of the holder. The spectrum is observed only through the eyepiece of the instrument and not with the naked eye close up and for a long time. It is forbidden to switch the spectroscope on without an installed lamp or with a lamp whose bulb is damaged, to dismantle the instrument, the lamps or the power unit or alter their design, to leave switched-on lamps unattended, and to apply a voltage above the one given in the passport. The external surfaces are wiped with a soft dry or slightly damp cloth, the optical elements, the slit, the scale and the eyepiece, are cleaned only with a dry soft brush or special optical paper without touching them with the fingers, the bulbs of the lamps are wiped only when cold and switched off and never by wet cleaning, and solvents, alcohol, acetone and chlorine-containing agents are not used. The integrity of the bulbs of all the lamps, especially the mercury one, and the state of the power cable and the contacts of the holder are checked periodically; the instrument needs no calibration by the user, and repair and maintenance are carried out only by an authorised service centre.
