Communication satellite link

Q. A T.V. transmission tower has height of $80m$. Radius of earth is $6400km$. What is the coverage range of tower?

1. $10km$
2. $12km$
3. $32km$
4. $64km$

Q. T.V. transmission tower at a particular station has a height of 160m:(a) What is its coverage range? (b) How much population is covered by transmission, if the average population density around the tower is ${1200km}^{-2}$? (c) By how much the height of tower be increased to double its coverage range? Given radius of earth = 6400km.

1. (a) 15255m
   (b) 87.24m
   (c) 480m
2. (a) 45255m
   (b) 77.24m
   (c) 480m
3. (a) 35255m
   (b) 77.24m
   (c) 280m
4. (a) 25255m
   (b) 97.24m
   (c) 180m

Q. T.V. tower has a height 100m. What is the population density around the T.V. tower if the total population covered is 50 lac? Radius of earth = $6.4\times {10}^{6}m$.

1. 3242.9${k/m}^2$
2. 2242.9${k/m}^2$
3. 4242.9${k/m}^2$
4. 1242.9${k/m}^2$

Q. A TV tower has a height of $75m$. The maximum distance and area up to which this TV transmission can be received is

1. $31km$, $3018{km}^2$
2. $30km$, $3000{km}^2$
3. $28km$, $2800{km}^2$
4. $25km$, $2500{km}^2$

Q. A T.V. tower at a height of 10 m is in a region of average population density $100\pi /k{m}^2$. The number of people that can receive the transmission is nearly

1. $1,28,000$
2. $2,56,000$
3. $64,000$
4. $32,000$

Q. Some of the important communication channels are

1. air
2. transmission line
3. free space
4. any of the above

Q. A long metal bar of $30cm$ length is aligned along a north south line and moves eastward at a speed of $10m{s}^{-1}$. A uniform magnetic field of $4.0T$ points vertically downwards. If the south end of the bar has a potential of $0V$, the induced potential at the north end of the bar is:

1. $+12V$
2. $-12V$
3. $0V$
4. $cannotbedeterminedsincethereisnotclosedcircuit$

Q. A TV tower is $120m$ high. How much more height is to added to it, if its coverage range is to become double?

1. $120m$
2. $240m$
3. $360m$
4. $480m$

Q. Intensity of electric field obtained at receiver antenna for a space wave propagation is

1. directly proportional to the perpendicular-distance from transmitter to antenna
2. inversely proportional to the perpendicular-distance from transmitter to antenna
3. directly proportional to the square perpendicular distance from transmitter to antenna
4. inversely proportional to the square perpendicular distance from transmitter to antenna

Q. At certain distance from a transmitting tower, a receiver tower of height $20m$ is used to receive direct signal. Another tower is installed beyond the first, along the same line of sight to receive the signals from the same transmitter. Its height is $44$% more than the first receiving tower. Then, the separation between the two receiving towers is (Radius of Earth = $6400km$)

1. $6.4km$
2. $3.2km$
3. $1.6km$
4. $0.8km$

Q. A radio receiver antenna that is 2 m long is oriented along the direction of the electromagnetic wave and receives a signal of intensity ${5\times 10}^{-16}{W/m}^2$ The maximum instantaneous potential difference across the two ends of the antenna is

1. $1.23\mu V$
2. $1.23mV$
3. $1.23V$
4. $12.3mV$

Q. To double the covering range of a T.V. transmitter tower, its height should be made:

1. $4$ times
2. $2$ times
3. $\sqrt{2}$ times
4. $8$ times

Q. To cover population of 20 lakh, a transmission tower should have a height of:

1. 25 m
2. 50 m
3. 75 m
4. 100 m

Q. A tank with vertical walls is mounted so that its base is at a height of $1.2m$ above the horizontal ground. The tank is filled with water to a depth $2.8m.$ A hole is punched in the side wall of thetank at a depth $xm$ below the surface of water to have maximum range of the emerging stream.Then the value of $x$ in meter is

1. $4.0$
2. $1.6$
3. $2.0$
4. $2.3$