Match List - I with List - II
List - I (Layer of atmosphere) |
List - II (Approximate height over earth's surface) |
||
---|---|---|---|
(A) | $$\mathrm{F_1}$$ - Layer | (I) | 10 km |
(B) | $$\mathrm{D}$$ - Layer | (II) | 170 - 190 km |
(C) | Troposphere | (III) | 100 km |
(D) | $$\mathrm{E}$$ - Layer | (IV) | 65 - 75 km |
Choose the correct answer from the options given below:
The amplitude of $$15 \sin (1000 \pi \mathrm{t})$$ is modulated by $$10 \sin (4 \pi \mathrm{t})$$ signal. The amplitude modulated signal contains frequencies of
A. $$500 \mathrm{~Hz}$$
B. $$2 \mathrm{~Hz}$$
C. $$250 \mathrm{~Hz}$$
D. $$498 \mathrm{~Hz}$$
E. $$502 \mathrm{~Hz}$$
Choose the correct answer from the options given below:
In satellite communication, the uplink frequency band used is :
A transmitting antenna is kept on the surface of the earth. The minimum height of receiving antenna required to receive the signal in line of sight at $$4 \mathrm{~km}$$ distance from it is $$x \times 10^{-2} \mathrm{~m}$$. The value of $$x$$ is __________.
(Let, radius of earth $$\mathrm{R}=6400 \mathrm{~km}$$ )