# 1st PUC Geography Question Bank Chapter 2 The Earth

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## Karnataka 1st PUC Geography Question Bank Chapter 2 The Earth

### 1st PUC Geography The Earth Text Book Questions and Answers

I. Answer the following in a word or a sentence each.

Question 1.
What is the approximate age of the Earth?
Answer:
Around 406 billion years.

Question 2.
Name the oldest proof in respect of shape of the Earth.
Answer:
The lunar eclipse.

Question 3.
Who conducted Bed Ford level experiment?
Answer:
Dr. Alfred Russel Wallace.

Question 4.
What is the total geographical area of the Earth?
Answer:
510 millim Sq km.

Question 5.
Who was the first person to calculate the distance between places?
Answer:
Eratosthenes, (276-195 Be), the Greek philosopher.

Question 6.
What is Earth’s axis?
Answer:
Earth axis is the imaginary line which goes through the north and south poles and around which the Earth spins. It is inclined at 66.50 from the Earth’s orbital plane, which means that it is tilted 23.5 degrees from a vertical to degrees.

Question 7.
What amount of time does the Earth take to complete one rotation?
Answer:
23 hours 56 minutes and 4.09 seconds.

Question 8.
Define Orbit.
Answer:
The fixed curved path in which the earth revolves around the sun is called orbit. The earth’s orbit is elliptical in shape. The earth takes 365 days to go around the sun.

Question 9.
On what date does the Summer Solstice occur?
Answer:
June 21st each year.

Question 10.
How many temperature zones are there on the globe?
Answer:
There are three temperature zones on the earth.

• Torrid or Tropical zone
• Temperate zone
• The Frigid zone.

II. Answer the following in two or three sentences each.

Question 1.
WhatisGeoid?
Answer:
The earth is not spherical but slightly flattened at the poles and bulged at the Equator. This shape is called ‘oblate spheroid’ or Geoid.

Question 2.
Mention the Equatorial and polar diameter of the Earth.
Answer:
The equatorial Diameter of earth is 12,756 kms Polar Diameter of earth is 12,714 kms.

Question 3.
Why are Northern and Southern hemispheres called as Land and Water hemisphere?
Answer:
The Northern hemisphere is covered with 60% land and 40% water. Hence it is called ‘ Land Hemisphere ’. The Southern Hemisphere is covered with 81 % water and 19% land mass. Hence it is called ‘Water hemisphere’.

Question 4.
Name the highest and lowest points on the land.
Answer:
Mt.Everest (8850 mts-Nepal) is the highest peak in the world and Dead sea (400 m below sea level Asia) is the lowest point on the land.

Question 5.
What is deflection of Winds?
Answer:
Deflection of winds:
The rotation of the Earth from east to west causes change in the direction of the wind. The winds deflect to its right in the Northern Hemisphere and towards the left in the southern hemisphere.

Question 6.
What is Inclination of the Earth?
Answer:
The earth’s axis is inclined at an angle of 66 to the plane of the orbit. This is known as ‘Inclination of the Earth’s axis’.

Question 7.
Distinguish between Perihelion and Aphelion.
Answer:
On January 3rd each year the Earth will be very close to the ‘perihelion’ the mean distance of the sun at this point will be 147 million kms form the Earth. On July 4th each year the Earth will be very far from the sun. This position is called ‘Aphelion’ The distance of the sun atthis point will be 152millionkmsoftheearth.

Question 8.
State the difference between Autumn Equinox and Spring Equinox.
Answer:
Autumn equinox:
On September 23rd each year the vertical rays of the sun falls on the Equator and therefore the days and nights First PUC Geography are Equal in both the hemispheres. This is known as ‘Autumn Equinox’. All countries in the Northern hemisphere experience Autumn Season which lasts three months when plants and trees shed their leaves.

Spring or Vernal Equinox:
On March 21st each year, the vertical rays of the sun fall on the Equator, when the duration of the days and nights are equal in both the hemispheres. It is the beginning of the spring Season in the North Hemisphere and continues upto June 20th. The Southern Hemisphere experiences Autumn Season. Trees and Plants bloom new leaves in the North Hemisphere.

Question 9.
Why is Norway called ‘Land of Mid-night Sun’?
Answer:
Norway is called the land of midninght sun. When the northern hemisphere is inclined towards the sun as a result of the earth’s revolution (the first six months of the year), places in the Northern Hemisphere have longer days and shorter nights and hence places at the north pole have almost months-long day and therefore, Nowray, being situated in the north pole experiences 20hr day and at night there is sun in the sky (northpole – 90°)

Question 10.
Mention the difference between Torrid and Temperate zones.
Answer:
1. Torrid zone or Tropical zone is the area between the Tropic of cancer $$23 \frac{1}{2}^{0} \mathrm{N}$$ and Tropic of capricorn $$23 \frac{1}{2}^{0} \mathrm{S}$$.

2. Frigid zone:
The region between the arctic circle to the North pole $$66 \frac{1}{2}^{0} \mathrm{N} \text { to } 90^{\circ} \mathrm{N}$$ ) in the Northern and the antartic circle to south pole $$66 \frac{1}{2} \text { s to } 900 \mathrm{S}$$ is known as ‘frigid zone’.

III. Answer the following:

Question 1.
Name and explain the proofs in support of the spherical shape of the Earth.
Answer:
Proofs in support of the spherical shape of the Earth: To Ascertain the Geoid shape of the Earth, several proofs are forwarded by experts. The most important among them are:
1. Heavenly bodies appear to be Spherical:
The Sun, the Moon and other heavenly bodies appear to be spherical when viewed from different position. The Earth is one of them and hence it must also be spherical is shape.

2. The Lunar Eclipse:
The lunar eclipse proves that the Earth is in spherical shape. During lunar eclipse when the Earth is between the Sun and the Moon, the shadow of the Earth falls on the Moon. Aristotle was the first scholar to show this by looking at the shadow of the Earth on the lunar surface. Later, this was ascertained by Ptolemy. This is considered to be the oldest proof in respect of the shape of the Earth.

3. Sunrise and Sunset:
The time of Sunrise and Sunset is not the same everywhere in the world. This is due to spherical shape of the Earth. If the Earth were to be flat all places on the Earth would have had sunrise and sunset at the same everywhere in the world. This is due to spherical shape of the Earth. If the Earth were to be flat all places on the Earth would have had sunrise and sunset at the same time everywhere in the world.

4. Circumnavigation:
Circumnavigation of the world can only be possible when the Earth is in sphe deal shape. If one start on a sea voyage towards the east, by moving constantly in the same direction, he would be able to complete a circle of the world and reach the Original point from where he had started.

5. The Bed Ford level experiment:
Dr. Alfred Russel Wallace conducted an experiment in 1956, along the Bed Ford level canal area in Britain. It is the most convincing proof of the curvature of the Earth. He fixed three poles of same height at an interval of about one mile apart and observed through a telescope.

It was found that the pole in the middle was higher than the other two poles (Fig.2.6). It is due to the curvature of the Earth. If the Earth were to be flat all the poles would have the same horizontal level.

6. Sighting a Ship:
A ship on the sea approaching the coast, when seen from the shore does not come into view all at once. The observer first sees the mast and then the hull and finally the whole ship. A ship moving away from the coast, disapppears gradually and finally out of view (fig.2.7). If the Earth were to be flat the whole ship would have come into view.

7. Aerial and Satellite Photographs:
The most clinching evidence of the Spherical shape of the Earth is obtained from aerial and satellite photographs taken from the space. This is considered to be the latest proof in respect of the shape of the Earth.

In addition to the above, spherical horizon, position of the Pole Star, weight of an object are also considered as some of the convincing proofs regarding the shape of the Earth.

Question 2.
Describe the size of the Earth.
Answer:
The ancient philosophers, Mathematicians said Geographers made several attempts to determine the size of the Earth The distance between places on the Earth was first calculated by a Greek Philosopher Eratosthenes (278-195 BC). He calculated the circumference of the Earth to be 2,52,000 stadia (measuring system Stades) or 46,250 km whichis very close to modem calculations.

The Equatorial circumference ofthe Earth is 40,076 km and the Polar circumference is 4f0,006 km. In the same way the Equatorial diameter of the Earth is 12,756 km and its Polar diameter is 12,714km, The difference of 70 km in circumference and 42 km in diameter is due to oblate spheroid or Geoid shape of the Earth.

According to size of the Planets, Earth is the fifth largest planet in the Solar System. The total geographical area ofthe Earth is 510 mil sq km. Of this, water bodies cover 361 mil sq km (71 %) and land massses Cover 149 mil sq km (29%). The ratio between land and waterbodies is 1:2.43.

Question 3.
How do seasons occur? Explain with a neat diagram.
Answer:
Rotation of the Earth pauses various effects. They are: day and Nights, deflection of winds, sense of time, identification of directions, longitudes, influenpe on the shape of the Earth, magnetic attraction, ocean currents, tides etc., .
Day and Night:
Day and nights are caused due to the rotation of the Earth. Qur Earth is a non-luminous body and it has to depend on the Sun’s light. If the Earth does no rotate there would be no day and night. The effect is one half of the Earth would always face the Sun and get illuminated and would always have day. The other half away from the Sun would remain dark and would always have night.

Defection of winds:
Rotation ofthe Earth from West to East cause change in the direction of winds i.e., to its right in the Northern hemisphere and to it left in the Southern hemisphere.

Sense of Time:
Earth’s rotation from West to East help us to understand and calculate the periodic change in time in a day. When the Sun rises from the horizon it is called noon and when it is setting it is said as evening and finally when there is no Sun’s light or darkness the period is called night. This happens due to regular spinning of the Earth on its axis.

Identification of directions:
Rotation of the Earth causes apparent movement of the Sun and other heavenly bodies. The direction in which the Sun rises is called East, the direction where the Sun sets is identified as West. Based on the Pole Star (North Star)North is identified and South is recognized on the basis of Southern Cross-a group of stars found is the Southern Sky.

Longitude and time:
Longitudes are the imaginary lines drawn on the globe from North pole to South Pole. These lines are marked on the spherical shape of the globe with the help of degrees. A sphere consists of360° and every line of longitude demarcates one degree. Rotation of the Earth influences the falling of direct Sun’s light on these longitudes one after the other.

The difference in the fall of Sun light is 4 minutes from one longitude to another and every 15 longitudes receive sun-light in 60 min or 1 hr. In the same way 180 longitudes get light in 12 hr and 360 longitudes receive light in 24 hr or 1 day.

Shape of the Earth:
The continuous Rotation of the Earth at high speed has it’s influence on the shape of the Earth. The bulging of the Equatorial region and flattening of the polar areas in due to rotation of the Earth. It is said that, when the Earth was formed it was in circular shape, now it has changed to spherical or Geoid and later may change into oval shape.

Magnetic attraction of the Earth:
The Earth acts as a huge magnet. The one end of the compass needle is always pointed towards the North pole because of high magnetic attraction in the pole caused by the rotation of the Earth.

Ocean currents:
Rotation of the Earth influences the movement of ocean water, particularly ocean currents. The ocean water flows continuously to it right in the northern hemisphere and to its left in the southern hemisphere from low latitudes to high latitudes due to rotation of the Earth and wind movement.

Tides:
The rise and fall in the sea level is called tides. Rotation of the Earth causes the facing of water bodies to the Moon. The gravitational attraction of the Moon and position of the water bodies cause tides. This is a regular phenomenon due to Earth’s rotation.

Apparent movement of the Sun, the Moon and other heavenly bodies:
Earth Rotates from west to east. Therefore, we can see the Sun, Moon and other heavenly bodies appearing to be rising in the east and setting in the west.

Question 4.
How do seasons occur? Explain with a neat diagram.
Answer:
Seasons occur due to the inclination and revolution of the Earth. The yearly movement of the Earth on its elliptical orbit takes the Earth to be in four important positions from the Sun. This results in causing cycle of seasons. They are:

• Summer Season
• Autumn Season
• Winter Season and
• Spring Season.

Of these Seasons two are Solstices (June 21st & December 22nd) and the other two are Equinoxes (September 23rd & March 21st). During Solstices the direct rays of the Sun falls either on the Tropic of Cancer or the Tropic of Capricorn and on Equinoxes it will be on the Equator.

Solstices influence on the variation in the length of day and nights (both hemispheres), while Equinoxes (Equinox: Equal nights) influence in getting equal length of days and nights (both hemispheres).

Summer Season (June 21 st to September 22nd):
On June 21st, due to the Earth’s inclination and revolution, vertical rays of the Sun fall on the Tropic of Cancer $$23 \frac{1}{2}^{0} North$$ Summer solstice. This is the beginning of Summer Season in the Northern Hemisphere (winter in SH) and continues up to September 22nd.

During this season the average temperature is high and days are longer and nights are shorter in all the countries of Northern Hemisphere and vice versa in the Southern Hemisphere. At this time the length of the day increases with the increase in latitude towards the North ofthe Equator.till north ofthe Arctic circle $$66 \frac{1}{2}^{0} \text { North }$$ as the North Pole is tilted towards the Sun.

There is no sun set to the north of the Arctic circle $$66 \frac{1}{2}^{0} North$$ during this period. Therefore, northern part of Norway (Hammeffest) lying to the north of the Arctic Circle receives Sun light for almost 24 hours and the Sun never sets below the horizon. So, Norqayis called ‘Land of mid-night Sun’. In this period the North pole feces the Sun fonsix months and the length ofday is six months.

Autumn Season (September 23rdlo December 21st):
On September 23rd, the vertical rays of the Sun falls on the Equator ‘Autumn Equinox’. Therefore, the days and nights are equal in both the hemishperes. This is the beginning of Autumn Season in all the countries of the Northern Hemisphere and it continues up to December 21st.

In this Season many plants and trees (natural vegetation) shed their leaves, known as ‘Fall Season’. During this period Southern Hemisphere witnesses Spring Season. This season lasts for three months.

Winter Season (December 22nd to March 20th):
On December 22nd, the vertical rays of the Sun falls on the Tropic of Capricorn $$23 \frac{1}{2}^{0} South$$ ’Winter solstice’. This is the begining of Winter Season in all the countries of the Northern Hemisphere and it continues till March 20th. In this period Southern Hemisphere record Summer Season.

During this season the average temperature is low and the days are shorter and nights are longer in the Northen hemesphere and it is vice versa in the Southern hemisphere. Counties situated above 500 North latitude record severe winter with high snow storms.

The areas coming under the l0 Antarctic Circle $$66 \frac{1^{0}}{2} \mathrm{S}$$ receive vertical sun rays as the South Pole is tilted towards the Sun, Hence, there is no sun set to the south of the Antarctic Circle. The South pole faces the Sun fox six months and the length of the days is also six months.

Spring Season (March 21st to June 20th):
On March 21st, the vertical rays of the Sun fells on the Equator Spring Equinox’ of ‘Vernal Equinox’. Therefore, the duration of days Midnights are equal in both the hemispheres. This is the beginning of spring in the Northern hemisphere and it continues up to June 20th. At the same time in the Southern hemisphere it will be Autumn.

In this season many plants and trees (natural vegatation) get new leaves and nature looks afresh with greeneries. This season lasts for three months and continues with fresh cycle of summer. In India, the beginning of the spring is considered very auspicious and is celebrated as the first day of the Year.

Question 5.
Describe the special latitudes and temperature zones of the globe with a neat diagram.
Answer:

Due to the Earth’s inclination at $$66 \frac{1}{2}^{0}$$ (orbit) and revolution, we recognize a few special latitudes (imaginary lines drawn on the globe from west to east) on the globe. The vertical rays of the Sun strike the Earth at different points at different times of the Year. On March 21st and September 23rd it falls on the middle of the Earth i.e., Equator (0°). On June 21st the vertical rays fall on $$23 \frac{1}{2}^{0}$$ North.

Tropic of Capricorn, and on December 22nd it falls on $$23 \frac{1}{2}^{0}$$ South – Tropic of Capricorn. On June 21st the Sun’s rays reach $$66 \frac{1}{2}^{0}$$ – North – Antarctic Circle, and on December 22nd the rays reach $$66 \frac{1}{2}^{0}$$ South – Antarctic circle.

The North pole (90° North) and South pole (90° South) are the two ends of the Earth’s axix. On the basis of special latitudes the globe may be divided into ‘Temperature zones’ or ‘Heat zones’. Direct rays of the sun produce more direct rays of the Sun. These rays are intense over a smaller area and so it heats up the Earth more.

As we go away from the equator, the sun’s rays strike the Earth’s surface with slanting rays, spreading over a larger area so, they do not heat as intensely as the direct rays. Therefore, when we go from the equator to the poles, we come across zones with varying temperatures.

The temperature zones are:

1. Torrid zone
2. Temperate zone and
3. Frigid zone.

1. The Torrid zone of Tropical zone:
The area between the Tropic of Cancer $$23 \frac{1}{2}^{0}$$ North and Tropic of Capricorn $$23 \frac{1}{2}^{0}$$ South ) is known as ‘Torrid zone Tropical zone.

2. The Temperate zone:
The area between the Tropic of Cancer and Auvic circle and Tropic of Capricorn and Antarctic circle $$23 \frac{1}{2} \mathrm{N} / \mathrm{S} \text { to } 66 \frac{1}{2}^{0} \mathrm{N} / \mathrm{S}$$ is known as ‘Temperate zone’.

3. The Frigid zone:
Between the Arctic circle to North pole $$66 \frac{1}{2}^{0} \mathrm{N} \text { to } 90^{\circ} \mathrm{N}$$ in the Northern Hemisphere and the Antarctic circle to South pole $$66 \frac{1}{2}^{0} \mathrm{S} \text { to } 90^{\circ} \mathrm{S}$$.

### 1st PUC Geography The Earth Additional Questions and Answers

Question 1.
Why is the Earth a ‘terrestrial planet’.
Answer:
The earth is a ‘terrestrial Planet’ as it is composed of silicate rocks or metals and has a solid sarface.

Question 2.
The earth is the only planet which supports life. Give reasons?
Answer:
The earth is the only planet which supports various forms of life, because of the atmosphere, presence of water and suitable distance from the sun.

Question 3.
Who was the first person to circumnavigate the world?
Answer:
Ferdinand MageUari (1519-1522) a Portuguese explorer is the first person to circumnavigate the world. ‘Victoria’ was the sole ship ofhis fleet to complete the circumnavigation.

Question 4.
Who is known as the ‘Father of Geography’.
Answer:
Eratosthenes (276 BC – 195 BC) is known as the father of Geography.

Question 5.
What is the reason for the difference between the Equatorial circumference and polar circumference of the Earth.
Answer:
The Oblate spheroid or Geoid shape ofthe Earth.

Question 6.
What is the ratio between land and water bodies of the earth.
Answer:
It is 1:2.43.

Question 7.
What is ‘Antipodal balance’.
Answer:
The arrangement of land and waterbodies on the Earth is called ‘Antipodal balance’. Land on the one side of the Earth is balanced by water on the other side, eg., The Arctic ocean is opposite to the Antarctic continent.

Question 8.
Which is the deepest point in the ocean floor.
Answer:
The Challenger deep (10,898 m or 35,755 ft) of Mariana trench in the Pacific Ocean near Philippenes islands in the deepest point in the ocean floor.

Question 9.
Who Proposed the Helio-centric theory?
Answer:
Nicolous Copernicus (1473-1543) a Polish astronomer proposed the Helio-centric theory.

Question 10.
What is the average speed ofnthe Rotation of the Earth?
Answer:
The average speed of the Rotation of the Earth is 1670 km/hr at the Equator (0° latitude) while at the poles it is o km/hr. ’

Question 11.
What it the length of the orbit of the earth?
Answer:
927 million kms.

Question 12.
What is the average speed of the revolution of the earth in its orbit?
Answer:
29.8 km/sec or 1,07,000 km/hr.

Question 13.
What is a ‘leap year?
Answer:
The Earth completes one revolution around the sun in 365 day First PUC Geography and 6 hours. A normal year consists of365 days. To compensate 6hr or 1/4 day, a day is added once in four years. The year having 366 days and particularly 29 day in the month of February is called a ‘Leapyear’. Any year divisible equally by 4 or 400 is considered as leap year.

Question 14.
What are the effects of the inclination and revolution of the earth?
Answer:
The inclination and revolution of the Earth causes.

1. Cycle of Seasons.
2. Variations in the length of day and night and
3. Identification of special Latitudes and Temperature zones.

Question 15.
Explain variation in the length of Day and Night.
Answer:
The variation in length of Day and Night is due to the inclination of the Earth’s axis and revolution. As one moves from the Equator to poles the duration of day and night is not equal; it changes from latitude to latitude. When the vertical sun rays are on the Tropic of Cancer (23 – N) or the Tropic of Capricorn ( 23 – S )the duration of day and night is longer.

In the North and South poles the duration will be 6 months due to the tilting of the poles towards the Sun. When the vertical rays of the sun is on the Equator the duration of day and night are equal (12 hr day and 12hr night).