(Online Cours) CAPF Assistant Commandant: Geography

Online Course for Central Armed Police Forces (CAPF) Exam (Assistant Commandant)



Important Facts

  • Biggest planet : Jupiter
  • Smallest plant : Mercury
  • Satellite of Earth : Moon
  • Nearest planet from Sun : Mercury
  • Farthest planet from Sun : Neptune
  • Nearest planet to Earth : Venus
  • Brightest planet : Venus
  • Brightest star : Dog Star
  • Planet having maximum
  • number of satellite : Jupiter (63)
  • Coldest planet : Neptune
  • Red planet (seen at night) : Mars
  • Heaviest planet : Jupiter
  • Biggest satellite of solar : Ganymede system
  • Smallest satellite of solar system : Demos
  • Blue planet : Earth
  • Red planet : Mars
  • Morning star : Venus
  • Evening star : Venus
  • Sister of Earth : Venus
  • 9th planet : Karla
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Distance from Earth: 149.6 million km (Approximately). Critical value of absolute visual magnitude 4.83
Diameter: 13,92,000 km
Temperature of Code: 20-15 million Celsius Apparent surface temperature: 5778°C (6000°C approximately)
Rotational period: 25 days, 3 hrs., 21 minutes, 136 seconds (in reference of equator) 33 days (in reference to pole)
Chemical composition: Hydrogen-69.5%, Helium-28%. Carbon, Nitrogen and Oxygen-2%, Magnesium, Sulphur, Silicon and Iron 0.5%
Age: 5 billion years (approximately)  Possible life of normal star 10 billion years (approximately)
Equatorial radius: 6,95,500 km (approximately)

Galaxy Name Magnitude Visual
Milky way
Large Magellanic Cloud 0.9
Small Magellanic Cloud 2.5
Ursa Minor Dwarf 11.9
Sculptor Dwarf 80
Draco Dwarf 10.9
Formax Sysyem 8.3
Leo -II System 12.04
Leo -I System 12.0
N. G.C 6822 8.9
N.G.C. 147 9.73
N.G.C. 185 10.1
N .G.C. 205 8.17
N.G.C. 2 21 (M 32) 8.16
IC 1613 9.61
Andromeda Galaxy 3.47
N.G.C. 598 (M 33) 5.79
Maffel I 11.0


Average distance: 3,84,365 km Diameter: 3,474 km
Ratio of mass in reference to Earth: 1:81.30
Density (with reference to water): 3.3464 kg/metre3
Density (with reference to Earth): 0.6058 Ratio in the gravitational force of Moon &
Sun: 0.116
Disappearing part of Moon: 0.41 Maximum distance of Earth from Sun 4,05,508 km
Minimum distance of Earth from Sun 3,63,300 km
Revolution period of the Moon round the Earth.
Sidereal Month: 27 days, 7 hrs, 43.25 minutes
Synodic Month: 29 days, 12 hrs, 44 minutes
Rotation on its own axis : 27 days, 7 hrs, 43 minutes, 11.47sec.
Atmosphere: Absent
Highest mts. Peak : 35,000 (Libtney, situated at Moon’s south pole).
Time taken by light to reach the earth.: 1.3 seconds.
Speed of Rotation at its own axis: 2287 miles per hrs.


Approximate age of Earth: 4600,000,000, years,
Total surface area: 510,072,000 km2
Total land area: 153,000,000 km2
Water area: 71% of the total land surface 357,100,000 km2
Average density: 5.52 gm per cub.cm.
Equatorial diameter: 12,756 km
Polar diameter: 12,714 km
Necessary escape velocity to cross the gravitational attraction of the Earth: 11.2 km/sec.
Velocity of a rocket to go against the gravitational attraction of the Earth 8 km /sec.
Distance from Moon: 3,84,365 km
Maximum height of the earth from M.S.L. 8848 m (Mount Everest)
Maximum depth of sea from M.S.L. : 11,033 metro (Mariana Trench)
Lowest part of the earth surface: 396 metre (Dead Sea)
Rotational period at its own axis: 23 hrs, 56 minutes 4.091 sec.
Revolution of earth round the Sun: 365 day, 5 hrs, 48 minutes, 45.51 second
Satellite of Earth: Moon
Inclination at its own axis: 23*-27.
Average distance from Sun: 149,597,887.5 km

Structure of the Earth:

The Earth is an oblate spheroid. It is composed of a number of different layers as determined by deep drilling and seismic evidence. These layers are:

  • The core which is approximately 7000 kilometer in diameter (3500 kilometer in radius) and is loc<.ted at the Earth’s center.
  • The mantle which surrounds the core and has a thickness of 2900 kilometer.
  • The crust floats on top of the mantle. It is composed of basalt rich oceanic crust and granitic rich continental crust.

The core is a layer rich in iron and nickel that is composed of two layers: The inner and outer cores. The inner core is theorized to be solid with a density of about 13 gram per cubic centimeter and a radius of about 1220 kilometer. The outer core is liquid and has a density of about 11 gram per cubic centimeter. It surrounds the inner core and has an average thickness of about 2250 kilometer. The mantle is almost 2900 kilometer thick and comprises about 83% of the Earth’s volume. It is composed of several different layers. The upper mantle exists from the base of the crust downward to a depth of about 670 kilometer. This region of the Earth’s interior is thought to be composed of peridotite, an ultramafic rock made up of the minerals olivine and pyroxene. The top layer of the upper mantle, 100 to 200 kilometer below surface, is called the asthenosphere. Scientific studies suggest that this layer has physical properties that are different from the rest of the upper mantle. The rocks in this upper portion of the mantle are more rigid and brittle because of cooler temperature and lower pressures. Below the upper mantle is the lower mantle that extends from 670 to 2900 kilometer below the Earth’s surface. This layer is hot and plastic.


The word lithosphere is derived from the word sphere, combined with ‘the Greek word lirhos. meaning rock. The litho-sphere is the solid outer section of Earth, which includes Earth’s crust (the “skin” of rock on the outer layer of planet Earth), as well as the underlying cool, dense, and rigid upper part of the upper mantle. The lithosphere extends from the surface of Earth to a depth of about 44-62 mi (70-100 km). This relatively cool and rigid section of Earth is believed to “float” on top of the warmer, non-rigid, and partially melted material directly below. Earth is made up of several layers. The outermost layer is called Earth’s crust. The thickness of the crust varies. Under the oceans, the crust is only about 3-5 mi (5-10 km) thick. Under the continents, however, the crust thickens to about 22 mi (35 km) and reaches depths of up to 37 mi (60 km) under some mountain ranges. Beneath the crust is a layer of rock material that is also solid, rigid, and relatively cool, but is assumed to be made up of denser material. This layer is called the upper part of the upper mantle, and varies in depth from about 31-62 mi (50-100 km) below Earth’s surface. The combination of the crust and this upper part of the upper mantle, which are both comprised of relatively cool and rigid rock material, is called the lithosphere. Below the lithosphere, the temperature is believed to reach 1,832°F (1,000°C), which is warm enough to allow rock material to flow if pressurized. Seismic evidence suggests that there is also some molten material at this depth (perhaps about 10%). This zone which lies directly below the lithosphere is called the asthenosphere, from the Greek word asthenes, meaning weak. The lithosphere, including both the solid portion of the upper mantle and Earth’s crust, is carried “piggyback” on top of the weaker, less rigid asthenosphere, which seems to be in continual motion. This motion creates stress in the rigid rock layers above it, forcing the slabs or plates of the lithosphere to jostle against each other, much like ice cubes floating in a bowl of swirling water. This motion of the lithospheric plates is known as plate tectonics, and is responsible for many of the movements seen on Earth’s surface today including earthquakes, certain types of volcanic activity, and continental drift.


Mouth of River Congo—Dio go kao (Portuguese) —1483
Cape of Good hope —Barto Lamen Diag—1488 (Portuguese)
Niger River —Munge Park (Scotland)—1795
Sahara Desert —Dixan-Danlam and Huge Clepraton (England)—1822-23
Zambegi River —David Living Stone (Scotland)—1851
Sudan —Hienerich Barth (Germany)—1852-53
Victoria fall —Livingstone (Scotland)—1855
Taganika Lake —Richard Bartan and John Spake (England)—1858
Congo River (entire) —Sir Hanery Stanley—1877

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