Endoscopy -

John  complained of severe stomach pain and started crying.  His elder brother consoled him and took  him to  gastroenterologist. Doctor advised for endoscopy and asked him to come next day with an empty stomach. John was not for the test he was afraid . However  his elder brother Jim was a medical student, explained the need for the test and told him that it was not a painful experience. He further explained that  a tube containing a fine  glass fibre would be inserted through the food pipe and light through this pipe would allow the doctor to  examine inside the stomach. Endoscopes can be directly  inserted into bladder, colon and other organs for direct visual examination. The test was done  and John felt good after taking medicine for two days .The coloured  X-ray image of a  patient's abdomen shows an endoscope winding through the colon is shown.

 

Question 1. What is the working principle of glass fibre  in the endoscope?

 

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Question 2. What are the two conditions for the light to travel along  the pipe?

 

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Question 3. The critical angle for glass is ........

               (a) 50°

               (b) 42°

               (c) 45°

               (d) 30°

 

Question 4. The outer concentric shell in the fibre optic is called........

               (a)   Cladding

               (b).   Core

               (c)   Mantle

               (d)    Coating

 

ANSWERS:-

 

1.          Full Credit :-Total Internal Reflection

Nil Credit :- No answer Or any wrong answer

2.          Full Credit :-the two conditions are. 1. light must travel from optically denser medium to optically rare medium  2. the angle of incidence in the denser medium must be greater than the critical angle

Half Credit :- For any one condition

Nil credit :- No answer Or any wrong answer

3.          Full Credit :- (b)42°

Nil Credit. :- No answer Or any wrong answer

            4.    Full Credit :- (a) Cladding

                    Nil Credit. :- No Answer or any other Answer