Question

Assertion Endoscopy involves use of optical fibres to study internal organs.
Reason Optical fibres are based on phenomenon of total internal reflection.

• A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
• B. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
• C. If Assertion is true but Reason is false.
• D. If both Assertion and Reason are false.

Answer 1

Answer: (A)

Optical fibre consists of a very long and thin fibre of quartz glass. When a light ray is incident at one end of the fibre making a small angle of incidence. It suffers refraction from air to quartz and strikes the fibre-layer interface at an angle of incidence greater than the critical angle. It therefore, suffers total internal reflection and strikes its opposte interface. At this interface also, the angle of incidence is greater than the critical angle. So, it again suffers total internal reflection. Thus, optical fibre is based on total internal reflection.
Endoscopy is a process for viewing internal organs of human body. This process use a device endoscope which is based on total internal reflection.