Geography · Physics

Geodesy and Celestial Mechanics

984 Questions

Geodesy and celestial mechanics questions explore Earth measurements, great circles, and planetary motions. These concepts form a crucial part of physical geography and astronomy in competitive exams. Practice these questions to grasp longitudinal and latitudinal calculations.

Longitude and latitude calculationsGreat circle conceptEarths axial precessionLagrangian pointsAtmosphere boundary

Geodesy and Celestial Mechanics Questions

Multiple choice evs - i communication and mass media understanding communication and impact of mass media satellites in communication importance of transport system artificial satellite

What fraction of the surface area of earth can be covered to establish communication by one geostationary satellite?

  1. $\displaystyle\frac{1}{2}$
  2. $\displaystyle\frac{1}{3}$
  3. $\displaystyle\frac{1}{4}$
  4. $\displaystyle\frac{1}{8}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We uses three geostationary satellites placed at the vertices of an equilateral triangle, then the entire earth can be covered by the communication network, each satellite covers $1/3$ of the globe.

Multiple choice

How far does the average person walk in a lifetime?

  1. once around the Earth

  2. the distance of the solar system

  3. 5 times around the Earth

  4. the circumference of the sun
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The average person walks about 100,000 miles in a lifetime, which is roughly equivalent to walking around the Earth's equator five times.

Multiple choice geography tides and ocean currents circulation of ocean water movements of ocean and sea water oceans : temperature, salinity and density oceanic circulations study of water pollution threats to water resource pollution and environment

How much area of the Earth surface is covered by Hydrosphere?

  1. 71%

  2. 75%

  3. 66%

  4. 70%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Approximately 71% of the Earth's surface is covered by water, which constitutes the hydrosphere.

Multiple choice geography in search of the source of wind global pressure belts pressure belts atmospheric conditions

The sub-polar high pressure belts lies around poles between 80 90 N and S latitudes.

  1. True

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

True,

Pressure Belts of Earth. On the earth's surface, there are seven pressure belts. They are the Equatorial Low, the two Subtropical highs, the two Subpolar lows, and the two Polar highs. Except the Equatorial low.

Multiple choice geography in search of the source of wind global pressure belts pressure belts atmospheric conditions

Subtropical high pressure belt lies close to the _______________.

  1. Equator

  2. Tropic of Cancer and Tropic of Capricorn

  3. North pole

  4. South pole
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Tropic of Cancer and Tropic of Capricorn
As it moves towards the mid-latitudes on both sides of the equator, the air cools and sinks. The resulting air mass subsidence creates a subtropical ridge of high pressure near the 30th parallel in both hemispheres.
The Tropic of Cancer is currently positioned at approximately 23.4 degrees north of the Equator. The Tropic of Capricorn is 23.4 degrees south of the Equator. The area between the Tropic of Cancer and the Tropic of Capricorn is often called the Tropics.
Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

'The parallax angle in radians is: $\theta = \left( 1 + \frac { 54 } { 60 } \right) \times \frac { \pi } { 180 } = 0.03316 \mathrm { rad }$
  Hence, the distance between moon and earth: 

  1. $\dfrac { \text { Diameter of Earth } } { \theta }$
  2. $\dfrac { 1.276 \times 10 ^ { 7 } m } { 0.03316 }$
  3. $3.84 \times 10 ^ { 8 } m$

  4. nnone of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given,

$\theta =0.03316\,\,rad$

Also $b = \mathrm { AB } =$ diameter of earth $= 1.276 \times 10 ^ { 7 } \mathrm { m }$

Now d $=\dfrac{b}{\theta }=\dfrac{1.276\times {{10}^{7}}}{0.03316\,}=3.84\times {{10}^{8}}\text{m}$

Hence, distance between earth and moon is $3.84\times {{10}^{8}}\text{m}$

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

What is the approximation made in the parallax method?

  1. All distances measured between two points on earth is zero.

  2. All distances measured between two points on earth is constant.

  3. Distance between a point on the earth and the planet is very large as compared to the distance between two points on earth's surface.

  4. No approximation is made.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In parallax method, an approximation is made that distance between a point on the earth and the planet is very large as compared to the distance between two points on the earth's surface.

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

Parallax angles _______ $0.01/ arcsec$ are very difficult to measure from Earth.

  1. more than

  2. less than

  3. equal to

  4. greater than or equal to
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parallax effect depends upon the path of light that travels from object to the observer. For distant objects observed from Earth, the light that reaches Earth has to go through a number of layers in Earth's atmosphere, during which it refracts and disperses and hence decreases the accuracy of the method. Resultantly parallax angles less than $0.01/arcsec$ are very difficult to measure from Earth.

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

A star is $1.45\ parsec$ light years away. How much parallax would this star show when viewed from two locations of the earth six months apart in its orbit around the sun?

  1. $2\ Parsec$
  2. $0.725\ Parsec$
  3. $1.45\ Parsec$
  4. $2.9\ Parsec$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One light year $=$ speed of light $\times$ one year

or $1 ly=3\times 10^8\times (24\times 3600)=94608\times 10^{11} m$
So, $4.29 ly=4.29\times (94608\times 10^{11})=4.058\times 10^{16} m$
As $1 $ parsec $=3.08\times 10^{16} m$
(Parsec is a unit of length used to measure large distances to objects outside our Solar System)
Thus, $4.29 ly=\dfrac{4.058\times 10^{16}}{3.08\times 10^{16}}=1.32$ parsec
Now angular displacement , $\theta=\dfrac{d}{D}$
where $d=$ diameter of earth's orbit $= 3\times 10^{11} m$ and 
$D=$ distance of star from the earth $=4.058\times 10^{16} m$
So, $\theta=\dfrac{3\times 10^{11}}{4.058\times 10^{16}}=7.39\times 10^{-6}$ rad
As $1 sec=4.85\times 10^{-6} rad$ so, $7.39\times 10^{-6} rad=\dfrac{7.39\times 10^{-6}}{4.85\times 10^{-6}}=1.52 sec$

Multiple choice magnetic compass magnetic poles and magnetic compass properties of magnet effect of electric current physics

The marked end of a compass needle always points directly to

  1. Earth's geographic South Pole

  2. Earth's geographic North Pole

  3. A magnet's south pole

  4. A magnet's north pole
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The marked end of compass needle always points to the south pole of a magnet.

The geographic north pole of the earth is the magnetic south pole. 
Hence it points towards the geographic north pole of earth.

Multiple choice magnetic compass magnetic poles and magnetic compass properties of magnet effect of electric current physics

At a certain location in Africa, compass points $12^0$ west of geographic north. The north tip of magnetic needle of a dip circle placed in the plane of magnetic meridian points $60^0$ above the horizontal. The horizontal component of earth's field is measured to be $0.16$G. The magnitude of earth's field at the location is :

  1. $0.32$G
  2. $0.42$G
  3. $4.2$G
  4. $3.2$G
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Here, $H _E = 0.16G = 0.16 \times 10^{-4}T$, dip angle $(\delta) = 60^0$
Then, magnitude of earth's field.
$B _E = \dfrac{H _E}{cos \delta} = \dfrac{0.16 \times 10^{-4}}{cos 60^0} T \Rightarrow B _E = \dfrac{0.16 \times 10^{-4}}{1/2} = 0.32 \times 10^{-4}T = 0.32G$

Multiple choice physics properties of a magnetic field earth - a gigantic magnet magnetic field of earth introduction to magnetic field and magnetic flux

The magnetic south pole of the earth is situated near the 

  1. geographic south pole

  2. geographic north pole

  3. geographic east

  4. geographic west
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

'Magnetic North' is a LOCATION, so-named to distinguish it from True North -it has NOTHING to do with its magnetic POLARITY. The magnetic polarity at this location is south -which is why it attracts the north-seeking pole of a compass needle or magnet.