Semi Circular Glass Slab
Product Code : SCL-LAO-11184
Quick answer: The Semi Circular Glass Slab is a D-shaped glass block used to measure refraction and find the critical angle. A ray aimed through the curved face at the centre of the flat face enters without bending, so only the flat face refracts it, which makes Snell's law, the critical angle and total internal reflection easy to show. Lab Exports manufactures it in Delhi for schools, colleges and universities.
Specifications
| Parameter | Detail |
|---|---|
| Shape | Semi-circular |
| Material | Optical glass |
| Edge work | Ground edges with polished viewing surfaces |
| Supplied with | Basic student instruction note for ray tracing |
How the critical angle experiment is done
Any ray travelling along a radius of the curved face meets that face at 90 degrees and passes straight through. If the ray is aimed at the centre of the flat face, it therefore reaches the flat face undeviated, and the only bending happens there, as the light leaves glass for air. Measuring the angle inside the glass and the angle outside gives the refractive index from n = sin r / sin i for light going from glass to air.
As the angle inside the glass is increased, the emerging ray bends further from the normal until, at the critical angle C, it runs along the flat face. Beyond that, all the light is reflected back into the glass: total internal reflection. The critical angle is linked to the refractive index by sin C = 1/n, about 42 degrees for common glass of n = 1.5.
- Place the slab flat on white paper or polar graph paper and trace its outline.
- Mark the centre of the flat face and draw the normal there.
- Direct a narrow ray from a ray box through the curved side towards the centre point.
- Mark the entry, centre and exit paths with small dots and join them.
- Increase the angle until the emerging ray just grazes the flat face, and measure this critical angle.
Key features
- Semi-circular shape, so rays aimed at the centre cross the curved face without bending.
- Polished viewing surfaces for clear ray tracks.
- Ground edges for safer handling.
- Suited to Snell's law, critical angle and total internal reflection practicals.
- Supplied with a basic student instruction note for ray tracing.
Documentation and supply
Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the semi circular glass slab at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
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- Glass Slab (SCL-LAO-11185)
- Optical Bench Full Shaper (SCL-LAO-11180)
- Optical Bench Half Shaper (SCL-LAO-11173)
- Optical Bench Ordinary (SCL-LAO-11172)
- Laser Ray Optics Kit (SCL-LAO-11170)
- Newton's Colour Disc Model (SCL-LAO-11215)
The full range is in the Light and Optics section of the Physics Lab range.
Frequently asked questions
Why is a semi-circular glass slab used for the critical angle experiment?
A ray aimed at the centre of the flat face travels along a radius and crosses the curved face without bending, so the only refraction occurs at the flat face, where the critical angle is measured.
What is the critical angle of glass?
For common glass with a refractive index of about 1.5, the critical angle is about 42 degrees, from sin C = 1/n.
What is the price of the semi circular glass slab?
Prices are not published on the website. Add the semi circular glass slab to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code SCL-LAO-11184 and the quantity, to receive a quotation.
Does Lab Exports manufacture the semi circular glass slab?
Yes. Lab Exports manufactures the semi circular glass slab at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code SCL-LAO-11184.
Request a quote
Email [email protected] with the house code SCL-LAO-11184 and the quantity, or add the semi circular glass slab to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
