Tag: moon and stars in sky

Questions Related to moon and stars in sky

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

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

  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

Show answer
Correct Option: D
Explanation:

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

The time period of geostationary satellite is :

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

  1. Zero

  2. $24 h$

  3. $12 h$

  4. $48 h$

Show answer
Correct Option: B
Explanation:

Answer is B.

A geostationary orbit can only be achieved at an altitude very close to $35,786$ km $(22,236 mi)$, and directly above the Equator. This equates to an orbital velocity of $3.07 km/s (1.91 mi/s)$ or an orbital period of $1,436$ minutes, which equates to almost exactly one sidereal day or $23.934461223$ hours, which is approximately $24$ hours.

The period of rotation of the geostationary satellite is ______ hours.

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

  1. 12

  2. 24

  3. 6

  4. 48

Show answer
Correct Option: B
Explanation:

A geostationary satellite is an earth-orbiting satellite, placed at an altitude of approximately 35,800 kilometers (22,300 miles) directly over the equator, that revolves in the same direction the earth rotates (west to east). 

At this altitude, one orbit takes $24 hours $, the same length of time as the earth requires to rotate once on its axis. 
The term geostationary comes from the fact that such a satellite appears nearly stationary in the sky as seen by a ground-based observer. 

Hence correct answer is option $B$ 

Two stones are projected with the same speed but making different angles with horizontal. Their ranges are equal. If the ranges of projection of one is $\pi/3$ and its maximum height is ${h} _{1}$ then the maximum height of the other will be

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

  1. $\dfrac{Rg}{\omega^{2}}$

  2. $\dfrac{R^{2}g}{\omega^{}}$

  3. $\dfrac{R^{2}g}{\omega^{2}}$

  4. $\dfrac{R^{2}\omega}{g^{}}$

Show answer
Correct Option: C
Explanation:

Assuming this to be a geo-stationary satellite, the angular speed of the satellite is the same as the angular speed of rotation of the earth. 

Hence, we have:
$GMm/r^2=mw^2r$ and $GM/R^2=g$
Hence, $r^3=R^2g/w^2$

The orbital angular velocity vector of a geostationary satellite and the spin angular velocity vector of the earth are

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

  1. always in the same direction

  2. always in opposite direction

  3. always mutually perpendicular

  4. inclined at 23 1/2 to each other

Show answer
Correct Option: A
Explanation:

For the satellite to be 'synchronous' with the Earth, its period of revolution should be equal to Earth's rotation. For this, the satellite has to revolve along the direction of Earth's rotation thus their angular velocity vector always point in the same direction.

A synchronous satellite should be at a proper height moving

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

  1. From West to East in equatorial plane

  2. From South to North in polar plane

  3. From East to West in equatorial plane

  4. From North to South in polar plane

Show answer
Correct Option: A
Explanation:

For the satellite to be 'synchronous' with the Earth, its period of revolution should be equal to Earth's rotation. For this, the satellite has to revolve along the direction of Earth's rotation that is from West to East.

The orbital period of revolution of an artificial satellite revolving in a geostationary orbit is ...

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

  1. 24 Hrs

  2. 48Hrs

  3. 12Hrs

  4. 6 Hrs

Show answer
Correct Option: A
Explanation:

For the satellite to be geostationary at equatorial plane, its time period should be equal to Earth's rotation time period i.e 24 hours.

Communication satellites are also referred to as:

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

  1. Polar satellites

  2. Geostationary satellites

  3. Launch vehicles

  4. Projectiles

Show answer
Correct Option: A
Explanation:

Communication satellites are also referred as Polar satellites. Polar satellites are those satellites that passes above or nearly above both the poles of the body orbited on each revolution and hence it has very close inclination of 90 degree's to the body's equator.

What are the general uses of satellite?

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

  1. Navigation

  2. Live telecast of programmer

  3. Both A and B

  4. None of these

Show answer
Correct Option: C
Explanation:

Satellite revolves around the earth with fixed a velocity in a circular orbit of certain radius. During its motion, satellite collects informative signals from earth and then sends those signal back to the other part of earth for interpretation. Satellites are generally used for navigation, live telecast of programmer, weather forecasting, communication purposes, GPS etc. 

A satellite placed in an orbit around Earth with certain speed will revolve in_______ as seen from Earth

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

  1. A helical path

  2. A circular path

  3. Straight line

  4. A parabolic path

Show answer
Correct Option: B
Explanation:

The centrifugal force acting on the satellite, revolving around the earth with certain velocity, is balanced by the gravitational force acting on it due to earth. The satellite keeps revolving around the earth in circular path of certain radius as seen from the earth.