Half-Round Optical Glass Slab

Product Code : SCL-LAO-12086

Half-Round Optical Glass Slab (SKU SCL-LAO-12086), also called a semi-circular glass slab, is a 90 mm diameter, 15 mm thick block of optical glass used to trace light rays across a glass-air boundary. Students use it to check Snell's law, find the critical angle and watch total internal reflection in Class 10–12 and B.Sc. physics. It is produced by Science Lab Supplies at Plot 448, HSIIDC Industrial Area, Saha, Ambala, India, which ships it straight to schools, colleges, contractors and distributors.

Specifications

The table lists every specification of the half-round slab. In brief, it is a semicircular block of crown or flint optical glass with a nominal refractive index of 1.5170, polished flat and curved faces, a frosted base that shows the ray path, and chamfered edges.

Applications and Experiments for the Half-Round Glass Slab

A ray aimed at the centre of the curved face meets it along the normal and passes straight through, so all bending happens at the flat face. That makes the slab simple physics lab equipment for measuring refraction angles, the critical angle of glass and total internal reflection.

• Class 10 science: refraction at a glass-air boundary, traced with pins such as the Optics Experiment Parallax Pin or a narrow beam.
• Class 12 physics: finding the critical angle and showing total internal reflection with a source such as the Five-Diode Laser Ray Box.
• B.Sc. practicals: plotting sin i against sin r to confirm Snell's law and estimate the refractive index.

Never look into the aperture of a laser source, and keep laser work under teacher supervision.

Standard Scope of Supply

Each slab is supplied with a velvet-lined storage pouch and an instruction sheet showing sample ray-tracing layouts. A light source, ray box, pins and tracing paper are not included; any of them can be quoted with the slab so a refraction practical is complete on arrival.

Packing, MOQ and Lead Time

Ask for one slab for a demonstration or a quantity for every student pair in the class. The quotation from Science Lab Supplies sets out the packing, delivery time and price for that number of slabs, and a ray box or rectangular slab can be priced alongside.

With an Importer-Exporter Code in place, Science Lab Supplies can ship to buyers in Oman, the Philippines, Nepal, Bangladesh, Zambia and Rwanda. Send your quantity through the contact page, collect items in the enquiry cart, or see the lab tender page for formal tenders.

Frequently Asked Questions

Why is a semicircular block used for refraction?
A ray directed at the centre point strikes the curved face at right angles to its tangent and enters without bending. Only the flat face refracts the ray, so the angles measured there belong to a single boundary.

How is the critical angle found with this slab?
Send the ray in through the curved side towards the centre of the flat face and increase the angle of incidence until the emergent ray grazes along the flat surface. The angle of incidence at that point is the critical angle.

Why is the bottom face frosted?
The frosted base scatters a little of the light travelling through the glass, so the path of the beam shows clearly on the paper worksheet underneath and can be traced with a pencil.

Is Science Lab Supplies the manufacturer or a trader?
Science Lab Supplies makes the half-round slab itself at its Saha, Ambala plant in Haryana. Because there is no intermediary, the quotation you receive is issued directly by the manufacturer.

Related Refraction Blocks and Ray Sources

These items cover the other blocks, prisms and light sources used in the same refraction and total internal reflection practicals. They can be combined with the half-round slab on one quotation to equip a school or college optics bench completely.

• Plane Glass Optical Slab — 100 x 60 x 15 mm rectangular crown glass block for lateral displacement.
• Glass Prism (Equilateral, 50 × 50 mm) — three polished 50 mm faces for dispersion and minimum deviation.
• Laser Refraction Chamber Set — built-in laser with four prisms, two mirrors and a beam splitter.
• Ray Box and Lens Set — 650 nm source with a hollow semicircular refraction cell and 310 x 210 mm board.
• Optical Ray Tracing Kit — magnetic 400 x 300 mm board with acrylic blocks and lenses.
• Ray Box Optics Activity Set — 12 V ray box with single, triple and five-beam slit shields.
• Rectangular Optical Light Box — dual-ended box with sliding shutters and RGB filters.

Browse the full Light and Optics range, the Physics Lab range for ray boxes and refraction sets, or all physics lab equipment.

Last updated: 9 October 2026