Tag: artificial satellite

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Questions Related to artificial satellite

Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

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.?

  1. $1^o$.
  2. $2^o$.
  3. $4^o$.
  4. $6^o$.
Reveal answer Fill a bubble to check yourself
B Correct answer
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 $2^o$.
Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

Which one of the following statements is correct?

  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 $3.07\times10^{2}m s^{-1}$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

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.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The time period of a satellite orbiting close to a spherical body is proportional to the square root of the inverse of density. Specifically, T equals 2 times pi times the square root of (R cubed over G M), which can be rewritten using density as T being inversely proportional to the square root of the density of the earth. Therefore, option C is correct while the other proportionality relations are incorrect.

Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

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 

  1. $4\pi R _{e}^{2}$
  2. $2\pi\sqrt{3} R _{e}^{2}$
  3. $2\pi(2-\sqrt{3}) R _{e}^{2}$
  4. $2\pi(4+\sqrt{3}) R _{e}^{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

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

  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. $\sqrt{\frac{R _{B}+R _{e}}{R _{A}+R _{e}}}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The orbital velocity of a satellite at distance r from the center of the earth is given by the square root of (G M over r). Here, the distances from the earth's center are r_A = R_A + R_e and r_B = R_B + R_e. Taking the ratio V_A over V_B gives the square root of (r_B over r_A), which matches option D.

Multiple choice evs artificial satellite types of artificial satellites geostationary orbits moon and stars in sky

To have an earth synchronous satellites it should be launched at the proper height moving from

  1. North to South in a polar plane

  2. East to West in an equatorial plane

  3. South to North in a polar plane

  4. West to East in an equatorial plane
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The sense of synchronous satellite must be same as the sense of rotation of earth i.e., from west to east