question_answer

Devansh was keenly watching the T-20 match of cricket with his uncle. The moment Virat Kohli made a sixer, suddenly the picture started shaking on TV screen. As he was disturbed, he came out in the balcony and saw a low flying aircraft passing over their house with a sound. Immediately his uncle explained the cause of shaking picture.

Read the above passage and answer the following questions :

(i) What kind of communication mode is used in TV transmission? How does a low flying aircraft disturb a picture in a TV?

(ii) What is the relation between coverage distance and height of transmitting antenna?

(iii) What values are reflected in the approach of Devansh's uncle?

Answer:

(i) Space wave propagation is used in TV transmission.

Low flying aircrafts reflects TV signals which interfere with direct signal causing disturbance in the picture.

(ii) Relation between coverage distance and height of transmitting antenna is

            \[{{d}_{M}}=\sqrt{2R{{h}_{T}}}+\sqrt{2R{{h}_{R}}}\] where,   R = radius of Earth, \[{{d}_{M}}\] = coverage distance, \[{{h}_{T}}\] = transmitting antenna height and       \[{{h}_{R}}\] = receiving antenna height.. (iii) Aware of technology, knowledge and analytical thinker.