Quick Answer:The Semi Circular Glass Slab is a D-shaped optical glass block with polished faces, a frosted base that shows ray paths, and bevelled safety edges, used for critical angle and total internal reflection experiments.
Last updated: 18 October 2026
Key Features
Semicircular (D-shaped) block with precision-ground edges.
Optically polished faces for clear refraction.
Frosted bottom face makes the ray path visible.
Bevelled edges reduce chipping.
Technical Specifications
Specification
Value
Shape
Semicircular (D type)
Faces
Optically polished
Base
Frosted, for ray visibility
Edges
Bevelled safety edges
How It Is Used
A narrow ray is aimed at the centre of the flat face so it passes along a radius and leaves the curved face without bending. Increasing the angle at the flat face shows refraction, then the critical angle and finally total internal reflection, from which students find the refractive index of the glass using Snell’s law.
Frequently Asked Questions
What is the Semi Circular Glass Slab used for?
Measuring the critical angle, demonstrating total internal reflection and finding the refractive index of glass with Snell’s law.
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