Question

One day Chetan’s mother developed a severe stomach ache all of sudden. She was rushed to the doctor who suggested an immediate endoscopy test and gave an estimate of expenditure for the same. Chetan immediately contacted his class teacher and shared the information with her. The class teacher arranged for the money and rushed to the hospital.On realizing that Chetan belonged to a below average income group family, even the doctor offered concession for the test fee. The test was conducted successfully. Answer the following questions based on the above information.
a)Which principle in optics is made use of in endoscopy?
b)Briefly explain the values reflected in the action taken by the teacher.
c) In what way do you appreciate the response of the doctor on the given situation?

Answer 1

Different properties of light waves are used in medical science to detect abnormalities in the function of different organs. One of them is endoscopy. We will see how the total internal reflection is used in case of endoscopy and then we will discuss the values shown by the class teacher and the doctor.

Complete answer:
a) The total internal reflection property of light is used in case of endoscopy. Endoscopy allows physicians to peer through the body's passageways. An endoscope uses two fiber optic lines. A "light fiber" carries light into the body cavity and an "image fiber" carries the image of the body cavity back to the physician's viewing lens.
In case of endoscopy we use optical fiber for total internal reflection of light so that there is minimum loss of intensity of light and we get to see the organ illuminated. The diagram is shown below.

The light incidents with an angle greater than the critical angle at the core-cladding interface and total internal reflection happens.
b) Class teacher was very generous and helpful. Knowing that Chetan belonged to a not so well to do family she arranged all the things for him. She is also very prompt in her action.
c) I appreciate it very much. In a country like India where most of the people do not belong to, well to do family medical expenses is a great problem for them. By offering concessions for the test fee the doctor showed great humanity and all the doctors should have an attitude like him. The government has a big role to play in the health sector.

Note:
When light falls in a rarer medium from a denser medium it bends to the opposite to the normal drawn i.e. the angle of refraction is greater than the angle of incidence. Now for a specific angle of incidence the light passes along the interface i.e. the angle of refraction becomes ${{90}^{0}}$ . This angle of incidence is called the critical angle. Light rays with an angle of incidence greater than the critical angle completely comes back to the first medium. This is called total internal reflection and it is applied in case of endoscopy.