Geomorphology

Question 1

Who gave the “theory of expanding universe”?

Answer 1

Edwin Hubble
Every celestial object is constantly moving away from each other.

Question 2

Geocentric World

Answer 2

Earth is the centre of the universe

Question 3

Heliocentric World

Answer 3

Sun is the centre of the world

Question 4

singularity

Answer 4

Around 13.7 billion years ago, everything in the entire universe was condensed in an infinitesimally small singularity, point of infinite denseness and heat

Question 5

“Big bang” theory was given by

Answer 5

Le Maitre and Gammow

Question 6

Earth spins on its axis from

Answer 6

west to east (counter-clockwise) rotation, and counter-clockwise revolution around the sun

Question 7

Aphelion

Answer 7

Earth is at its maximum distance from the sun at aphelion (on 4 July ) aka July Aphelion

Question 8

Perihelon

Answer 8

Earth is at its minimum distance from the sun at perihelon (on 4 January) aka January Perihelon

Question 9

Apogee , Perigee

Answer 9

the point in the moon’s orbit where it is farthest from the earth is called apogee , while it’s closest approach is known as perigee

Question 10

Summer solstice/June solstice

Answer 10

April-August
NH=> tilted towards the sun->longer days & shorter nights
SH=>tilted away from sun->shorter days & longer nights

21st June=> NH: Longest day
SH: Longest night

Arctic region will not experience night: continuous daytime
Antarctic region will not experience daytime: continuous night

Question 11

Equinox

Answer 11

both hemispheres receive equal sunlight
equal length of day and night (equinox)
21st March (Vernal Equinox) & 23rd September (Autumnal equinox)

Question 12

Winter Solstice/December Solstice

Answer 12

October-February

22nd December=>
NH: Longest night
SH: Longest day

NH is tilted away from sun => shorter days & longer nights -> winter season

SH is tilted towards the sun-> Longer days & shorter nights -> Summer season

Arctic region does not receive sunlight during this time-> continuous night
Antarctic region during these months does not experience night->continuous day

Question 13

Name the major latitudes

Answer 13

Arctic circle 6634’ N
Tropic of Cancer 2326’N
Equator 0*
Tropic of Capricorn 2326’S
Antarctic circle 6634’S

Question 14

The international dateline is not straight, why?

What happens when you cross the dateline?

Answer 14

The dateline runs from the North pole to the South pole and marks the divide between the western and eastern hemisphere.
It is not straight but zigzags to avoid political and country borders and to not cut some countries in half.

When you cross the International Date Line from west to east, you subtract a day, and if you cross the line from east to west , you add a day

Question 15

What is a Milankovitch cycle

Answer 15

.Change in axial tilt
increases or decreases the rate of heating & cooling’ specially around polar regions (21½-24 , average 23½*)

.Orbit changes from elliptical to circular(eccentricity-every 100,000 years)

Question 16

Asthenosphere

Answer 16

.semi-solid ,semi-molten state
.upper portion of mantle
.’astheno’:weak
.main source of magma that find its way to the surface during volcanic eruption
.presence of radioactive material like uranium and potassium
.excess heat produced due to a thermo-nuclear reaction [partially melts the substance]

Question 17

Describe the interior of the earth alongwith the sources of information

Answer 17

Direct Source:
.Mining & Digging
.Volcanic Eruption

Indirect Source:
.Seismic waves[Energy waves generated during earthquakes]
.Meteorites
.Gravitational & magnetic field

*crust
*mantle
*outer core (molten)
*inner core (solid)→ despite of the very high temperature it is not allowed to expand owing to very high pressure & hence it is in solid state

Question 18

Crust

Answer 18

.outermost solid part
.represent 1% of earth’s mass
.mean thickness of oceanic crust: 5km
continental crust:30 km {70 km thick in himalayan region}
.difference in density (OC is heavier than CC)
.CC composed chiefly of granite has a density of 2.7 g/cm³
.type of rock found in OC is basalt, mean density of material in OC is 3g/cm³

Question 19

Mantle

Answer 19

.portion of the interior of earth beyond the crust
.represents about 68% of earth’s mass
.density around 3.4g/cm³ higher than crust portion
{Density increases as we move to a greater depth}

Question 20

Core

Answer 20

.makes about 31% of the earth
.inner core solid state
.outer core is in liquid state sue to extreme pressure exerted from top which doesn’t allow the materials to expand
.core is made up of very heavy material constituted by “nickel & iron” hence, aka “nife” layer

Question 21

Discontinuities inside the earth

Answer 21

.CONRAD DISCONTINUITY
between upper and lower crust
.MOHOROVICIC DISCONTINUITY
between lower crust and upper mantle
.REPITI DISCONTINUITY
between upper and lower mantle
.GUTTENBERG DISCONTINUITY
between lower Mantle and outer core
.LEHMANN DISCONTINUITY
between outer and inner core

Question 22

Minerals in the interior of the earth

Answer 22

.earth as a whole
Iron>Oxygen>Silicon>Magnesium>Sulphur>Nickel>Calcium>Aluminum

.earth’s crust
Oxygen>Silicon>Aluminum>Iron>Calcium>Calcium>Magnesium>Sodium>Potassium

Question 23

Igneous rocks

Answer 23

.primary rocks
.formed through the cooling and solidification of the magma or lava
.may form with or without crystallization, either below the surface as intrusive (plutonic: solidification of magma) rocks {e.g.: diorite, granite, pegmatite}

or in the surface as extrusive (volcanic: solidification of lava) {e.g.: basalt, tuff, pumice}, grain size is much smaller-> cooling is faster

Question 25

types of rocks formed on the basis of origin

Answer 25

.Igneous rocks {formed as a result of solidification of the magma or lava}
.sedimentary rocks {solidification of deposits happening as a result of compaction, contains organic matter & fossil fuels}
.metamorphic rocks

Question 26

types of rocks formed on the basis of minerals present

Answer 26

.MAFIC
darker, denser, rich in Iron and magnesium
.FELSIC
lighter, less dense, rich in silica and feldspar.

Question 27

Sedimentary rocks

Answer 27

.resultant of deposits
.based on the source of deposits it can be classified as:
* clastic :mechanical breakage {sandstone, siltstone}
* chemical :chemical action {Iron ore, limestones}
* organic :organic deposits {coal: formed as a deposit of remains of trees and wood}

Question 28

Metamorphic rocks

Answer 28

may be formed simply by being beneath the earth’s surface, subjected to high temperatures and great pressure of the rock layers above it or in mountainous regions {limestone->marble}

.FOLIATED M.R.
appears layered by the exposure to heat and pressure.
{phyllite, gneiss}
.NON-FOLIATED M.R.
don’t have layers
{marble, quartzite}