Tag: geostationary orbits

Questions Related to geostationary orbits

The distance of the moon from the earth is about 60 times the radius of the earth. What will be diameter of the earth (approximately in degrees) as seen from the moon.?

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  1. $1^o$.

  2. $2^o$.

  3. $4^o$.

  4. $6^o$.

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Correct Option: B
Explanation:

From figure
We know the formula 

$\theta=\dfrac{Diameter \ of \ earth}{R}$

$\displaystyle \theta = \frac{2R _E}{60 R _E}$

$= \dfrac{1}{30} rad = \dfrac{1}{30} \times \dfrac{180^o}{\pi} = 2^o$

The diameter of the earth as seen from the moon is about $2^o$.

LANDSAT series of satellite move in near polar orbits at an altitude of

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  1. 3600km

  2. 3000km

  3. 918km

  4. 512km

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Correct Option: C
Explanation:

LANDSAT 1 through $3$ operated in a near-polar orbit at an altitude of $920 km$ with an $18-day$ repeat coverage cycle. These satellites circled the earth every 103 min completing $14$ orbits a day

Which one of the following statements is correct?

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  1. The energy required to rocket an orbiting satellite out of earth's gravitational influence is more than the energy required to project a stationary object at the same height (as the satellite) out of earth's influence.

  2. If the zero of potential energy is at infinity, the total energy of an orbiting satellite is negative of potential energy.

  3. The first artificial satellite Sputnik I was launched in the year 1950.

  4. The orbital speed of the SYNCOMS (synchronous communications satellite) is $3.07\times10^{2}m s^{-1}$

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Correct Option: D
Explanation:

The energy required to rocket an orbiting satellite out of earth's gravitational influence is less than the energy required to project a stationary object at the same height (as the satellite) out of earth's influence.
Hence, option (a) is incorrect statement.


If zero of potential energy is at infinity, the total energy of an orbiting satellite is negative of its kinetic energy.
Hence, option (b) is an incorrect statement.

The first artificial satellite was launched by Soviet scientists in the year 1957.
Hence, option (c) is an incorrect statement.

The orbital speed of the SYNCOMS is $v=\dfrac{2\pi{r}}{T}=\dfrac{2\times3.14\times4.22\times10^{7}}{8.64\times10^{5}}$
$=3.07\times10^{2}m s^{-1}$
Hence, option (d) is a correct statement.

Out of the following, the only correct statement about satellites is

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  1. A satellite cannot move in a stable orbit in a plane passing through the earth's centre

  2. Geostationary satellites are launched in the equatorial plane

  3. Satellites are rectangular in shape. 

  4. Geostationary satellites are launched in axial plane

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Correct Option: B
Explanation:

Geostationary satellites are launched to the equitorial plane, so the it could have a time period of 24 hours exact and can have maximum reach, i.e on both heminpheres for information transfer.

State whether the given statement is True or False :

It is possible to put an artificial satellite into orbit in such a way that it will always remain directly over New Delhi.

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  1. True

  2. False

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Correct Option: B
Explanation:

Geostationary satellite appears to be stationary above particular point on the Earth. We can have geostationary satellites only above equator. If it is not above the equator then it will change its position relative to particular position of the Earth which we do not want. 

Since New Delhi is not on the equatorial plane and geostationary satellite is launched on the equatorial plane, so the satellite will not remain directly over New Delhi. 
Therefor, the given statement is false.

The time period of an orbiting satellite is (assuming spherical earth)

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  1. Directly proportional to the density of earth

  2. Directly proportional to the square of density of earth

  3. Inversely proportional to the square root of density of earth

  4. Inversely proportional to the density of earth

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Correct Option: D

A satellite is orbiting around the earth in an orbit in equatorial plane, of radius 2$R _{e}$ , where $R _{e}$ is theradius of the earth. Find the area on the earth, this satellite covers for communication purpose in its complete revolution 

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  1. $4\pi R _{e}^{2}$

  2. $2\pi\sqrt{3} R _{e}^{2}$

  3. $2\pi(2-\sqrt{3}) R _{e}^{2}$

  4. $2\pi(4+\sqrt{3}) R _{e}^{2}$

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Correct Option: A

Identify the correct full form of IRNSS from the following

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  1. Independent  regional navigation satellite system

  2. International regional national satellite system

  3. Indian regional national service system

  4. indian regional nevigation satellite system.

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Correct Option: A

Two satellites A & B go around the earth in a circular orbits at a heigh of $R _{A} & R _{B}$ respectively from surface of the earth. Assume earth to be a uniform sphere of radius $R _{e}$ The ratio of the magnitudes of velocities of the satellite $V _{A}/V _{B}$ is

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  1. $\sqrt{\frac{R _{A}}{R _{B}}}$

  2. $\left ( R _{A}/R _{B} \right )^{2}$

  3. $\frac{R _{B}+R _{e}}{R _{A}+R _{e}}$

  4. $\sqrt{\frac{R _{B}+R _{e}}{R _{A}+R _{e}}}$

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Correct Option: A

For a satellite to be geostationary, which of the following are not essential conditions?

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  1. It must always be stationed above the equator

  2. It must be rotated from west to east

  3. It must be about $36000 \mathrm { km }$ above the Earth

  4. Its orbit must be circular, and not elliptical

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Correct Option: A