A light year is a measure of distance and not of time. Light travels at a speed of 300,000 km/second. Considering this, the distances the light will travel in one year is taken to be one light year. This equals to 9.461×1012 km. The mean distance between the sun and the earth is 149,598,000 km. In terms of light years, it is 8.311minutes.

“Statement 4 is incorrect:
Jovian planets have thick atmosphere and not terretsrial planets.
Out of the eight planets, mercury, venus,
earth and mars are called as the inner planets
as they lie between the sun and the belt of
asteroids the other four planets are called the outer planets. Alternatively, the first four are called Terrestrial, meaning earth-like as they are made up of rock and metals, and have relatively high densities. The rest four are called Jovian or Gas Giant planets. Jovian means jupiter-like. Most of them are much larger than the terrestrial planets and have thick atmosphere, mostly of helium and hydrogen.”

“Statements 2 and 3 are incorrect:
Direct sources-
The most easily available solid earth material is surface rock or the rocks we get from mining areas. Many deep drilling projects have provided large volume of information through the analysis of materials collected at different depths.

Volcanic eruption forms another source of obtaining direct information. As and when the molten material (magma) is thrown onto the surface of the earth, during volcanic eruption, it becomes available for laboratory analysis.

Indirect sources-
Analysis of properties of matter indirectly provides information about the interior.

Another source of information are the meteors that at times reach the earth. However, it may be noted that the material that becomes available for analysis from meteors, is not from the interior of the earth. The material and the structure observed in the meteors are similar to that of the earth.

They are solid bodies developed out of materials same as, or similar to, our planet. Hence, this becomes yet another source of information about the interior of the earth.

The other indirect sources include gravitation, magnetic field, and seismic activity.”

“Earthquake waves are basically of two types — body waves and surface waves.
Body waves are generated due to the release of energy at the focus and move in all directions travelling through the body of the earth. Hence, the name body waves. The body waves interact with the surface rocks and generate new set of waves called surface waves.
Surface waves move along the surface. The velocity of waves changes as they travel through materials with different densities. The denser the material, the higher is the velocity. Their direction also changes as they reflect or refract when coming across materials with different densities. There are two types of body waves. They are called P and S-waves.
P-waves move faster and are the first to arrive at the surface. These are also called ‘primary waves’. The P-waves are similar to sound waves. They travel through gaseous, liquid and solid materials.
S-waves arrive at the surface with some time lag. These are called secondary waves. An important fact about S-waves is that they can travel only through solid materials.
There exist some specific areas where the waves are not reported. Such a zone is called the ‘shadow zone’. The zone between 105° and 145° from epicentre was identified as the shadow zone for both the types of waves. The entire zone beyond 105° does not receive S-waves. Hence, the shadow zone of S-wave is much larger than that of the P-waves.”

“Primary activities- Agriculture, forestry, fishing and mining
Secondary activities- Manufacturing
Tertiary activities- Transport, communication and other services
Quaternary activities- Research and development”

“The earthquake events are scaled either
according to the magnitude or intensity of
the shock. The magnitude scale is known as
the Richter scale. The magnitude relates to
the energy released during the quake. The
magnitude is expressed in numbers, 0-10.
The intensity scale is named after Mercalli,
an Italian seismologist. The intensity scale
takes into account the visible damage caused
by the event. The range of intensity scale is
from 1-12.”

“Batholith is a large body of magmatic material that cools in the deeper depth of the crust develops in the form of large domes. They appear on the surface only after the denudational processes remove the overlying materials.
Lacoliths are large dome-shaped intrusive bodies with a level base and connected by a pipe-like conduit from below.
Whenever a lava, while moving upwards, develops into a saucer shape, it is called lapolith.
A wavy mass of intrusive rocks, at times, is found at the base of synclines or at the top of anticline in folded igneous country. Such wavy materials have a definite conduit to source beneath in the form of magma chambers (subsequently developed as batholiths). These are called the phacoliths.”

“Sea floor spreading theory was given by “”Hess””.
Main points of his theory are as follows:
(i) All along the mid-oceanic ridges, volcanic eruptions are common and they bring huge amounts of lava to the surface in this area.
(ii) The rocks equidistant on either sides of the crest of mid-oceanic ridges show remarkable similarities in terms of period
of formation, chemical compositions and magnetic properties. Rocks closer to the mid-oceanic ridges have normal polarit and are the youngest. The age of the rock increases as one moves away from the crest.
(iii) The ocean crust rocks are much younger than the continental rocks. The age of rocks in the oceanic crust is nowher more than 200 million years old. Some of the continental rock formations are as old as 3,200 million years.
(iv) The sediments on the ocean floor are unexpectedly very thin. Scientists were expecting, if the ocean floors were as old as the continent, to have a complete sequence of sediments for a period of much longer duration. However, nowher was the sediment column found to be older than 200 million years.”

“Some important minor plates are listed below:
(i) Cocos plate : Between Central America
and Pacific plate
(ii) Nazca plate : Between South America
and Pacific plate
(iii) Arabian plate : Mostly the Saudi Arabian
landmass
(iv) Philippine plate : Between the Asiatic and
Pacific plate
(v) Caroline plate : Between the Philippine
and Indian plate (North of New Guinea)
(vi) Fuji plate : North-east of Australia.”

“Statements 1 and 3 are incorrect:
Sedimentary Rocks
The word ‘sedimentary’ is derived from the Latin word sedimentum, which means settling. Rocks (igneous, sedimentary and metamorphic) of the earth’s surface are exposed to denudational agents, and are broken up into various sizes of fragments. Such fragments are transported by different exogenous agencies and deposited. These deposits through compaction turn into rocks. This process is called lithification.
Depending upon the mode of formation, sedimentary rocks are classified into three major groups:
(i) mechanically formed — sandstone, conglomerate, limestone, shale, loess etc. are examples;
(ii) organically formed — geyserite, chalk, limestone, coal etc. are some examples;
(iii) chemically formed —chert, limestone, halite, potash etc. are some examples.
Metamorphic Rocks
The word metamorphic means ‘change of form’. These rocks form under the action of pressure, volume and temperature (PVT) changes. Metamorphism is a process by which already consolidated rocks undergo recrystallisation and reorganisation of materials within original rocks. In the process of metamorphism in some rocks grains or minerals get arranged in layers or lines. Such an arrangement of minerals or grains in metamorphic rocks is called foliation or lineation. Sometimes minerals or materials of different groups are arranged into alternating thin to thick layers appearing in light and dark shades. Such a structure in metamorphic rocks is called banding and rocks displaying banding are called banded rocks.”

“Statement 1 is incorrect because cirques are formed by action of glaciers. The landforms formed by the action of glaciers.

The landforms formed by the action of groundwater are as follows:
Erosional landforms
1. Pools
2. Sinkholes
3. Doline
4. Uvalas
5. Lapies
6. Caves
7. Limestone pavements
Depositional landforms
1. Stalactites
2. Stalagmites
3. Pillars”

“Statement 1 is incorrect because stacks are erosional landforms formed by action of waves and currents.

Depositional landforms by all types of agents
are mentioned below:

1. Running water
a) Alluvial plains
b) Deltas
c) Floodplains
d) Natural levees
e) Point bars

2. Groundwater
a) Stalactites
b) Stalagmites
c) Pillars

3. Glaciers
a) Moraines
b) Eskers
c) Outwash plains
d) Drumlins

4. Waves and currents
a) Beaches and dunes
b) Bars
c) Barriers
d) Spits

5. Winds
a) Sand dunes”

“The atmosphere consists of different layers
with varying density and temperature. Density is highest near the surface of the earth and decreases with increasing altitude. The column of atmosphere is divided into five different layers depending upon the temperature condition. They are: troposphere, stratosphere, mesosphere, thermosphere and exosphere.
The troposphere is the lowermost layer of the atmosphere. Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator.
The zone separating the tropsophere from stratosphere is known as the tropopause.
The stratosphere is found above the tropopause and extends up to a height of 50 km. One important feature of the stratosphere is that it contains the ozone layer.
The mesosphere lies above the stratosphere, which extends up to a height of 80 km. The upper limit of mesosphere is known as the mesopause. The ionosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions, and hence, it is known as ionosphere.”

“Statement 4 is incorrect:
Tikdam: In this question, if you would have been able to eliminate statement 4, then all the options except option 1 would have been eliminated because statement 4 is common in all options except option 1.

The troposphere is the lowermost layer of
the atmosphere. Its average height is 13 km
and extends roughly to a height of 8 km near
the poles and about 18 km at the equator.
Thickness of the troposphere is greatest at
the equator because heat is transported to
great heights by strong convectional currents.
This layer contains dust particles and water
vapour. All changes in climate and weather
take place in this layer. The temperature in
this layer decreases at the rate of 1° C for every 165m of height. This is the most important layer for all biological activity.
The zone separating the tropsophere from
stratosphere is known as the tropopause. The
air temperature at the tropopause is about
minus 80 degree C over the equator and about minus 45 degree C over over the poles. The temperature here is nearly constant, and hence, it is called the tropopause.
Radio waves transmitted from the earth are reflected back to the earth by ionosphere.”

“The decreasing order of the presence of these gases in the atmosphere is as follows:
Nitrogen > Oxygen > Carbon dioxide > Helium
> Hydrogen”

“The amount and the intensity of insolation vary during a day, in a season and in a year. The factors that cause these variations in insolation are :
(i) the rotation of earth on its axis;
(ii) the angle of inclination of the sun’s rays;
(iii) the length of the day;
(iv) the transparency of the atmosphere;
(v) the configuration of land in terms of its aspect.
The last two however, have less influence.”

“The transfer of heat through horizontal
movement of air is called advection. Horizontal movement of the air is relatively more important than the vertical movement. In middle latitudes, most of dirunal (day and night) variation in daily weather are caused by advection alone. In tropical regions particularly in northern India during summer
season local winds called ‘loo’ is the outcome
of advection process.”

“Both the statements are incorrect:

The insolation received by the earth is in short waves forms and heats up its surface. The earth after being heated itself becomes a radiating body and it radiates energy to the atmosphere in long wave form. This energy heats up the atmosphere from below. This
process is known as terrestrial radiation. The long wave radiation is absorbed by the atmospheric gases particularly by carbon dioxide and the other green house gases. Thus, the atmosphere is indirectly heated by the earth’s radiation.

The atmosphere in turn radiates and transmits heat to the space. Finally the amount of heat received from the sun is returned to space, thereby maintaining constant temperature at the earth’s surface and in the atmosphere.”

“The temperature of air at any place is
influenced by:
(i) the latitude of the place;
(ii) the altitude of the place;
(iii) distance from the sea, the air-mass circulation;
(iv) the presence of warm and cold ocean currents;
(v) local aspects.”

“Normally, temperature decreases with increase in elevation. It is called normal lapse rate. At times, the situations is reversed and the normal lapse rate is inverted. It is called

Inversion of temperature. Inversion is usually of short duration but quite common nonetheless. A long winter night with clear skies and still air is ideal situation for inversion. The heat of the day is radiated off during the night, and by early morning hours, the earth is cooler than the air above. Over polar areas, temperature inversion is normal throughout the year.”