Quick answer. Ask for the focal length against every lens and mirror code before you order. OPL-0001 to OPL-0062, with three appended codes, covers the whole school and college optics bench, yet almost no lens or mirror entry states a focal length, and every lens and mirror practical depends on one. Get the focal length and tolerance, diameter, mounting and material in writing for each code. Then order the sources the experiments assume, above all the sodium lamp OPL-0044 with its ballast and housing for spectrometer and polarimeter work, and put two rules on the wall: no telescope at the sun, and no mercury lamp with a damaged envelope.
Sixty-five items are listed here, OPL-0001 to OPL-0062 with three further codes appended, covering the whole school and college optics bench: lenses and mirrors, prisms and blocks, ray boxes, optical benches, spectrometers and spectroscopes, polarimeters, telescopes, discharge tubes and optical glass. One specification is missing from almost every lens and mirror entry and it is the only one that matters when you order: the focal length. Ask for it against every code. Two safety rules also belong on this page before anything else: no telescope is ever pointed at the sun, and a mercury vapour lamp is never run with its outer envelope broken or removed.
| Topic | Codes | Apparatus |
|---|---|---|
| Lenses | OPL-0003 to OPL-0009 | Spherical and cylindrical lenses, double convex and concave, plano-convex and plano-concave, and a set of six |
| Mirrors | OPL-0012 to OPL-0018 | Plane, circular, concave, convex, cylindrical concave and convex, and a support block |
| Prisms and blocks | OPL-0032 to OPL-0037, OPL-0024, OPL-0043 | Glass equilateral and right-angle prisms, perspex equivalents, hollow prism, rectangular perspex block, set of acrylic blocks |
| Ray tracing and colour | OPL-0010, OPL-0019, OPL-0023, OPL-0038 to OPL-0041 | Light box with optics kit, Newton's disc, magnetic optical disc, ray optics and colour-mixing boxes, ray optics kit, ray track apparatus |
| Benches and measuring | OPL-0022, OPL-0053, OPL-0054, OPL-0060 | One-metre wooden optical bench, spherometers, travelling microscope |
| Interference and diffraction | OPL-0002, OPL-0020, OPL-0021 | Diffraction gratings, Newton's rings apparatus and its measuring microscope |
| Spectra | OPL-0045, OPL-0050, OPL-0051, OPL-0052, OPL-0061, OPL-0062 | Spectrometers, spectroscopes including a direct-vision hand instrument, Geissler tubes and their supply |
| Polarisation | OPL-0029, OPL-0030, OPL-0031 | Polarimeter, polarimeter tubes, polarising filters |
| Sources and photometry | OPL-0001, OPL-0011, OPL-0044, OPL-0025, OPL-0026 | Compact light source, mercury vapour lamp, sodium vapour lamp, grease-spot photometer, Jolly's photometer |
| Telescopes and cameras | OPL-0055 to OPL-0059, OPL-0027, OPL-0028 | Astronomical, terrestrial, reflecting and reading telescopes, pinhole camera and kit |
| Optical glass | OPL-0046 to OPL-0049 | Borosilicate crown, dense flint, extra dense flint, double extra dense flint |
| Other | OPL-0042 | Rectangular tank for refraction in liquids |
Every lens and mirror experiment in a syllabus specifies a focal length, and no entry in this listing states one. Ask, for each code: the focal length and its tolerance; the diameter or clear aperture; whether the component is loose or mounted in a holder, and if mounted, whether the holder fits the optical bench you are buying; and the material and surface quality, since a moulded perspex component and a polished glass one behave differently and scratch very differently. For the set of six lenses (OPL-0009), ask which six focal lengths it contains before assuming it covers your practicals.
For the optical bench (OPL-0022), ask how many riders or holders are supplied and what they hold, because the standard experiment needs a source, an object, a lens and a screen on the bench at once and a bench with two riders cannot run it. Ask the scale length and division, and whether the uprights allow the components to be brought to the same height, which is the usual reason a bench experiment will not line up.
Five codes here cover ray tracing: a light box with optics kit (OPL-0010), a ray optics and colour-mixing box (OPL-0038), a ray optics box (OPL-0039), a ray optics kit (OPL-0040) and a ray track apparatus (OPL-0041). Ask for the contents list of each and buy one. The things that make a ray box work are not in any of the names: whether the lamp is a line filament, which is what gives a sharp single ray rather than a fuzzy band; how many slits are provided and whether single, double, triple and parallel-beam masks are included; whether colour filters come with it; and whether the components in the kit are perspex blocks and prisms or glass. Ask also what the box runs on, since a mains-powered ray box needs a socket at every bench.
OPL-0011, mercury vapour lamp. Treat this as the item on the page with a real hazard. A mercury discharge lamp emits ultraviolet, and the outer glass envelope is what absorbs it. If that envelope is cracked, chipped or removed, the inner arc tube emits ultraviolet that burns eyes and skin, and the injury appears hours later with no sensation at the time. So: inspect the envelope before every use, never operate a lamp whose envelope is damaged, do not look into the lamp, and allow it to cool fully before handling. The lamp also contains mercury, which means it is disposed of as mercury-containing waste and not in the general bin, and the same international restrictions discussed under Fluid Mechanics Physics Equipments are worth checking against your import rules. Ask the supplier for the lamp's own instructions and ask whether a mercury-free monochromatic source would serve your experiments.
OPL-0044, sodium vapour lamp. This is the standard monochromatic source for spectrometer, diffraction grating and polarimeter work, and in practice it is the lamp those experiments assume, so order it together with them rather than afterwards. It runs very hot and needs time to cool before handling, it takes several minutes to reach full output, and a broken lamp should be handled with care and disposed of properly rather than swept up loose. Ask whether the choke or ballast and the lamp housing are included, because the lamp alone will not light.
For both, and for the compact light source (OPL-0001), tell students not to look directly into a bright source, and set the apparatus up so the beam travels across the bench rather than towards eye level.
No telescope here is ever pointed at the sun. Concentrated sunlight through any telescope causes permanent eye damage instantly and without warning, and it will also destroy the instrument's eyepiece. That rule goes in the laboratory notice and in the practical sheet, and a telescope kept in a school should have its finder capped so nobody can sight through it casually.
Three of the five telescope codes are described as models (OPL-0055 astronomical model, OPL-0057 terrestrial model) alongside what appear to be working instruments (OPL-0056 astronomical, OPL-0059 reflecting), so ask of each whether it is a demonstration model showing the optical arrangement or a usable telescope. For a usable one, ask the objective aperture and focal length, the eyepieces supplied and their focal lengths, the resulting magnifications, and the mount, since an astronomical telescope on an inadequate mount is unusable whatever its optics. OPL-0058, the simple reading telescope, is a different thing again: it belongs with the spectrometer and Newton's rings work rather than with astronomy, so ask its working distance.
For the spectrometers (OPL-0045, OPL-0050) ask the vernier least count, the collimator and telescope focal lengths, whether the prism table levels and rotates with a scale, and whether a prism or a grating is supplied with it, since a spectrometer without either cannot be used. For the diffraction gratings (OPL-0002) ask the lines per millimetre of each grating supplied and whether they are replica or ruled. For the spectroscopes, ask whether the scale is calibrated in wavelength and what it is calibrated against.
For the polarimeter (OPL-0029) ask the tube lengths supplied (OPL-0030), the scale least count, and what source it needs, which is normally the sodium lamp above; a polarimeter bought without a monochromatic source cannot run the standard sugar-concentration experiment. Ask whether the polarising filters (OPL-0031) are mounted and what their extinction is.
Geissler tubes (OPL-0061) run on a high-voltage supply (OPL-0062). Ask the supply voltage, whether the output terminals are shrouded, whether the tube holder insulates the connections, and whether the supply has any current limiting. Nobody adjusts connections with the supply energised, the tubes get hot in use, and this is a staff-operated demonstration rather than a student practical. Ask whether the supply is required or whether an induction coil you already own will serve.
OPL-0046 to OPL-0049 are named by glass type alone, borosilicate crown through to double extra dense flint, which tells you nothing about what you receive. Ask what form each is supplied in, a prism, a slab or a block, its dimensions, and above all the refractive index and the dispersion, because the only reason to buy dense flint rather than crown is the index and dispersion figures, and without them the specimen cannot be used for a comparative measurement.
For the spherometers (OPL-0053, OPL-0054) ask the least count and whether a plane reference glass is supplied; for the travelling microscope (OPL-0060) ask the vernier least count on both axes, the travel in each direction, and the objective magnification, since this instrument is the measuring device for Newton's rings and capillarity work and its least count sets the accuracy of both.
Quote the code rather than the name. Most names in this listing are in capitals with a "for physics lab" suffix, one carries the word spectroscope twice, apostrophes are missing from Newton's, Jolly's and Geissler's, one name misspells polarising filters, two prism codes are out of sequence, and three items at the end of the listing carry a code prefix and format belonging to another category, so a name alone is not enough to order from. Ask also for the quantity per student group, glassware breakage spares, the manual with the expected result, the supply voltage, frequency and plug type for your country for every lamp, and the warranty. Any figure quoted is confirmed in writing on the quotation; ask for its basis.
Wave behaviour, interference and the ripple tank are under Physics Sound and Waves Lab. The travelling microscope and spherometer are also used in the expansion and surface-tension work under Heat and Engine Physics Lab Equipments and Fluid Mechanics Physics Equipments. Photocells and light-dependent devices sit with Electricity and Cell Lab, and general apparatus under Mechanics Physics Lab. Parent range: Physics Lab Equipments.
Send your optics practical list and ask for focal lengths against every lens and mirror code. For example Double Convex Spherical Lens (OPL-0008) in the focal lengths your experiments need, eight groups, with the one-metre optical bench (OPL-0022) and the number of riders stated, plus the sodium vapour lamp (OPL-0044) with its ballast and housing if you are ordering the spectrometer or polarimeter. Contact Ray Export for prices, focal lengths and lead times.
For each lens and mirror code, ask the focal length and its tolerance, the diameter or clear aperture, whether it is loose or mounted and whether the holder fits your bench, and the material, since moulded perspex and polished glass behave and scratch differently. For the set of six lenses (OPL-0009), ask which six focal lengths it holds. For the one-metre optical bench (OPL-0022), ask how many riders are supplied and what they hold, because the standard experiment needs a source, an object, a lens and a screen at once, and whether the uprights bring components to the same height.
One, after comparing contents. Five codes overlap: the light box with optics kit (OPL-0010), the ray optics and colour-mixing box (OPL-0038), the ray optics box (OPL-0039), the ray optics kit (OPL-0040) and the ray track apparatus (OPL-0041). What makes a ray box work is not in any name: a line filament lamp, which gives a sharp single ray rather than a fuzzy band; the number of slits and whether single, double, triple and parallel-beam masks are included; whether colour filters come with it; and whether the blocks and prisms are perspex or glass. A mains-powered box needs a socket at every bench.
It is the item on this page with a real hazard. A mercury discharge lamp emits ultraviolet, and the outer glass envelope is what absorbs it. If the envelope is cracked, chipped or removed, the inner arc tube emits ultraviolet that burns eyes and skin, and the injury appears hours later with no sensation at the time. Inspect the envelope before every use, never run a lamp with a damaged envelope, do not look into it, and let it cool before handling. The lamp contains mercury, so dispose of it as mercury-containing waste, and ask whether a mercury-free monochromatic source would serve.
A monochromatic source, normally the sodium vapour lamp OPL-0044, so order it with them; a polarimeter without one cannot run the standard sugar-concentration experiment. Ask whether the choke or ballast and housing are included, because the lamp alone will not light, and note that it runs very hot and takes several minutes to reach full output. For the spectrometers (OPL-0045, OPL-0050), ask the vernier least count, the collimator and telescope focal lengths, whether the prism table levels and rotates against a scale, and whether a prism or grating is supplied. For the gratings (OPL-0002), ask lines per millimetre.
Ask of each code. OPL-0055 and OPL-0057 are described as astronomical and terrestrial models, while OPL-0056 and OPL-0059 appear to be working astronomical and reflecting telescopes. For a usable telescope, ask the objective aperture and focal length, the eyepieces and their focal lengths, the resulting magnifications and the mount, since an astronomical telescope on a poor mount is unusable. OPL-0058, the reading telescope, belongs with spectrometer and Newton's rings work, so ask its working distance. And one rule covers them all: no telescope is ever pointed at the sun, and finders should be capped when stored.
The Geissler tubes (OPL-0061) run on a high-voltage supply (OPL-0062), so ask the supply voltage, whether the output terminals are shrouded, whether the tube holder insulates the connections and whether the supply limits current. Treat it as a staff-operated demonstration: nobody adjusts connections while it is energised, and the tubes get hot. Ask whether an induction coil you already own would serve instead. The optical glass codes OPL-0046 to OPL-0049 are named by glass type alone, so ask the form supplied, the dimensions and, above all, the refractive index and dispersion, which are the only reason to choose dense flint over crown.
Ray Export is a manufacturer and exporter of laboratory, scientific and educational equipment based at Plot No. 449, HSIIDC Industrial Area, Saha, Ambala, Haryana 133104, India. Enquiries: [email protected], +91-9817319615.
Written by Palak Mall, Senior Content Writer. Technically reviewed by Arvind Kumar, Lab Equipment Specialist, 12+ years in laboratory and testing instrumentation. Last updated: 17 October 2026.
Specifications for the OPL codes, including focal length and tolerance, diameter, mounting, least counts, grating rulings and the refractive index and dispersion of the optical glass, are confirmed in writing on the quotation. For lamp or electrical safety documents, contact us for the latest copies of the relevant certificates. No price is quoted on this page. Listing note: focal length is missing from almost every lens and mirror entry; most names are in capitals with a for physics lab suffix; one name repeats the word spectroscope; apostrophes are missing from Newton's, Jolly's and Geissler's; one name misspells polarising filters; two prism codes are out of sequence; and three appended items carry another category's code prefix and format.
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