Question

Ravi is a student of mechanical engineering studying in one of the engineering colleges. The other day he saw an old man who suddenly collapsed as he walked out of the house in his neighbourhood. Ravi rushed towards him immediately made a call to the nearby hospital asked for the ambulance and took him to the emergency ward of the hospital. On getting the medical aid, the old man soon got recovered. he did not forget to thank Ravi for the timely help he rendered. He was wondering that in his times to get the telephone connection, one had to wait for years whereas these days it takes no time to get the connection. Ravi told him it was all because of the technological progress/development due to which the simple phenomenon in physics could be easily used. Answer the following questions based on the above:

(i) To which phenomenon in physics was Ravi referring to, which made the land line links so easily accessible ? 

(ii) What are the essential conditions required to observe this phenomenon ? 

(iii) Write two values displayed by Ravi and the old man in this episode.

Answer 1

(i) Ravi was referring to the phenomenon of total Internal Reflection

Alternatively :

Development of techniques for rapid transmission of e.m. waves/ setting up of linking network (pr development of mobile telephony)

(ii) Condition required for the occurrence of total internal reflection :

1. Angle of incidence > Critical Angle

2. Light should travel from denser to rarer medium

Alternatively:

(a) Setting up of appropriate transmission cable network/antennas

(b) Availability of appropriate transducers (or setup of mobile cell network)

(iii) Ravi

Helpful (concerned) nature

Oldman

Thankful (Grateful)