Name: Ray Diagram: Lenses
Uploaded: 2019-07-19
Duration: 6 min 35 s
Description: In this video, let us discuss how ray diagrams for lenses can be used to determine the size and location of a refracted image. Get in to know more!

Question

Explain the working of an endoscope.

Accepted Answer

An endoscope is an illuminated optical, typically slender and tubular instrument used to look deep into the body and used in procedures called an endoscopy.

Its construction is based on the principle of total internal reflection of light , When a light travelling from a medium of higher refractive index to a lower one at an angle more than the critical on the interface of two medium , it bounces back in the same medium.

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Optical fibre consist of several thousand of very long fibres of glass or quartz of refractive index 1.5.. The fibres are coated with thin layer of material of lower refractive index (1.48) this is cladding.

The light incident on one end of the fibre at a small angle enter the fibre after refraction and strike the core / cladding surface at an angle more than the critical angle between the two surfaces and suffers total internal reflection repeatedly. The light thus travels in a zig-zag manner to the other end without loss of intensity.

In Endoscope a light source is fitted at one end of the optical fibre and an eyepiece/ camera at the other end

Light from the source is passed through the outer fiber The light is illuminated on the internal part of the body. The reflected light from the object is brought to focus using the telescope to the inner fiber

As a result, the whole picture is reproduced at the other end of the receiving fiber as shown in the figure. The output is properly amplified and can be viewed through the eye piece at the receiving end.

Explain the working of an endoscope.

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