RBSE Solutions for Class 11 Physical Geography Chapter 3 The Earth: Form, Motions, Location and Calculations of Time

Rajasthan Board RBSE Class 11 Physical Geography Chapter 3 The Earth: Form, Motions, Location and Calculations of Time

RBSE Class 11 Physical Geography Chapter 3 Text Book Questions

RBSE Class 11 Physical Geography Chapter 3 Multiple Choice Questions

Question 1.
The international date line passes through which longitudinal line?
(a) 0° longitude
(b) 150° longitude
(c) 180° longitude
(d) 82 \(\frac { { 1 }^{ \circ } }{ 2 } \) longitude
Answer:
(c) 180° longitude

Question 2.
All the country’s clocks are in accordance with the accepted time period, this time is called:
(a) Local time
(b) Mid – value time
(c) Apparent time
(d) Standard time
Answer:
(d) Standard time

Question 3.
Which country has the most number of time zones?
(a) Russia
(b) Canada
(c) China
(d) U.S.A.
Answer:
(a) Russia

Question 4.
Equinox means:
(a) The position of the Sun’s perpendicular on the tropic of cancer
(b) Perpendicular position of the sun on tropic of capricorn
(c) Position of sun perpendicular on the equator
(d) Perpendicular position of sun on both torpics of caneer and capricorn
Answer:
(c) Position of sun perpendicular on the equator

Question 5.
Timing is calculated on all the time zones :
(a) 180° longitude
(b) 0° meridian
(c) 90° east longitude
(d) from Greenwich
Answer:
(b) 0° meridian

RBSE Class 11 Physical Geography Chapter 3 Very Short Answer Type Questions

Question 1.
By how many degrees is the axis of the Earth tilled?
Answer:
The axis of the Earth is tilled at \(\frac { { 1 }^{ \circ } }{ 2 } \).

Question 2.
Where is the speed of rotation on Earth the highest?
Answer:
The highest speed of rotation on Earth is 1600 kilometers per hour on the equator.

Question 3.
What is the position of greatest distance between the Sun and Earth ?
Answer:
When the earth is at the greatest distance from the Sun, then this position is called Aphelion.

Question 4.
What is the speed of Revolution?
Answer:
The earth’s movement around the sun in an elliptical orbit. This speed of earth’s revolution is 29.6 kilometers per second.

Question 5.
What is the total number of Longitudes?
Answer:
The total number of Longitudes on the globe is 360.

RBSE Class 11 Physical Geography Chapter 3 Short Answer Type Questions

Question 1.
The international date line is drawn along which longitude?
Answer:
The international date line is drawn with the help of 180° latitude. But this line does not lie from one end of the 180° longitude to its other end. In many places, this line deviates from the 180° longitude and describes a zig – zag path because 180° longitude passes through the many islands of the Pacific Ocean which are governed by one country, so to ensure no difference in date, this line is zig – zag as needed.

Question 2.
In what place is the prime meridian line fixed?
Answer:
The prime meridian line has been drawn in north-south direction from a place called ‘Greenwich’, located near London. It is displayed as a 0° longitude line. This line passes through France, Spain, Algeria, Mali, Togo, Ghana, Burkina Faso, etc. The time of this line is considered to be the world’s international time. The time of standard longitudinal lines of the whole world is positive or negative in the context of this line.

Question 3.
Into how many times zones has Canada been divided and why?
Answer:
Canada has been divided into five. In five time zones of Canada, the local times of 60°, 75°, 90°, 105° and 120° west longitudes are taken as standard times of five time zones. Canada is a nation with a vast geographical area. It is a extended more from east to west. It is divided into five time zones, due to the greater intra – regional expansion from east to west.

Question 4.
What tool is used to know local time?
Answer:
The time according to the longitude of each place is called its local time. This time can be determined precisely by a sun – clock. The local time is related to the height of the mid-day. From this, on the same longitude, all cities in the north – south have the same local time. So there is no difference in their local time. Local time is always in accordance with the position of mid – day sun overhead.

Question 5.
Mention the name of the line to the west of which new day is effected and to the east of which the old day remain the same.
Answer:
The international date line is such a longitude that determines the dates of the world. This is 180° longitude line. The day is determined by this line. As this line is crossed to wards the west towards Asia. The place which is on the west side of this line, that is, Asia, there is a new day. Whereas, the earlier day remains for the East side, i.e., that of America.

RBSE Class 11 Physical Geography Chapter 3 Essay Type Questions

Question 1.
Explain the difference between local and standard time.
Answer:
Difference between local and standard time:
Local time and standard time are defined in the context of an area. Both these times have been described as follows:

Local Time:
The time calculated according to the longitude of each location is called its local time. This time can be determined precisely by the Sun’s position overhead. The local time is related to the height of the mid – day sun. It has the same time in the entire north – south of all the cities on the same longitude. So there is no difference in their local time. The cities located in the East – West will be on different longitudinal position of the lines. Because of this, it is natural to have difference distances in the local time of the cities located in them. Local time is always in accordance with the position of the midday.

Standard Time:
Local time can be current for a town. But when we reach another place while travelling, then there is a difference in time. In such a state, while travelling towards East or West, to keep the correct time, it is necessary to keep your watch four minutes forward or backward after crossing each longitude. To overcome this difficulty, there is a standard time in every nation.

For standard time, any one longitude in each country is assumed to be ‘standard longitude line’. The standard time line of England is 0° longitude, which passes through Greenwich. Often a country treats the local time of a place located on a suitable longitude its an standard time. The longitude of that city is of great importance to that country. Watches from all the cities of the country are set according to the time of the city located on this standard time line. Thus, the time of a place which is considered standard for all the places in a particular country is called the standard time of that country.

Question 2.
The standard time of a country or region is actually the local time of a specific meridian. Explain this statement citing India’s example.
Answer:
There is a standard time in every nation. This time is valid in all parts of that country. This standard time is determined by a certain line. This determination of time is always positive or negative as referred to the Greenwich Meridian. The standard time line of England is 0° longitude, which longitudinal through Greenwich.

Often the nation takes the local time of a certain place located on an appropriate longitude as standard time. The longitude of that city is of great importance to that country. Watches from all the cities of the country are set according to the time of the city located on the standard line. Thus, the time of any particular place is considered as the standard time of that country.

In the context of India:
To determine the standard time in India, 82\(\frac { { 1 }^{ \circ } }{ 2 } \) east longitude is considered to be the standard time line. If our fixed location is on the 82\(\frac { { 1 }^{ \circ } }{ 2 } \) line then according to our local meridian, our clock will show 12 at 12 o’clock. But if our position is located before this line, then 12 hours in our clock will show after midday and if the place is located in the west then the clock will show 12 o°clock before midday.

If the standard time is not considered and every place begins to accept its own local time, all public activities will be disturbed. The difference between the standard time and international time of each country is kept in multiples of 1 hour or \(\frac { 1 }{ 2 }\) hour. The standard time of India is the local time of 82 \(\frac { { 1 }^{ \circ } }{ 2 } \) meridian.

According to this line, the clock strikes 12 o’clock in Arunachal Pradesh and Dwarka in Gujarat together. Otherwise, they have about 2 hours of difference in their local times. Due to the 82 \(\frac { { 1 }^{ \circ } }{ 2 } \) standard time line, in entire India.

Question 3.
What is the International Date Line? Explain its importance.
Answer:
The 180° longitude line, located in the opposite direction of the prime meridian (0° longitude), is called the International Date Line. If we circumnavigate the entire world, our clock undergoes a difference of 24 hours (180° East – 180° West), thus there is a difference of 1 day in both places. The journey from east to west will decrease one day and the journey from West to East will increase one day. In order to overcome this difficulty, different nations have unanimously determined the international date range with reference to the 180° longitude line.

Importance of International Date Line:
Taking reference from the International Date Line, the date is determined all over the world. Its importance can be understood through the following points:

1. This line removes the variation in time of 1 day that occurs upon circumnangating the earth, out to be revolving around the world-which is the difference of one day.
2. Due to the assumption of daybreak (dawn) in accordance to this line, the determination of the day in the world becomes simpler.
3. Travelling from east to west of the international date line, time decreases by 1 day. While travelling from west to east, one day increases.
4. If the international date line is not determined, then the same date cannot be found across the world.

The international date line is depicted through the following diagram:

RBSE Class 11 Physical Geography Chapter 3 Other Important Questions

RBSE Class 11 Physical Geography Chapter 3 Multiple Choice Questions

Question 1.
Earth’s equatorial diameter is:
(a) 10,256 km
(b) 12,756 km
(c) 14,656 km
(d) 16,556 km
Answer:
(b) 12,756 km

Question 2.
What is the polar perimeter of the Earth?
(a) 20,000 km
(b) 30,000 km
(c) 40,000 km
(d) 50,000 km
Answer:
(c) 40,000 km

Question 3.
By many degrees is the earth tilted on its axis?
(a) 13\(\frac { { 1 }^{ \circ } }{ 2 } \)
(b) 23\(\frac { { 1 }^{ \circ } }{ 2 } \)
(c) 33\(\frac { { 1 }^{ \circ } }{ 2 } \)
(d) 44\(\frac { { 1 }^{ \circ } }{ 2 } \)
Answer:
(b) 23\(\frac { { 1 }^{ \circ } }{ 2 } \)

Question 4.
What is the distance between all the latitudes?
(a) 90 km
(b) 111 km
(c) 191 km
(d) 241 km
Answer:
(b) 111 km

Question 5.
Which of these has been called the prime meridian line?
(a) Equator
(b) Tropic of Cancer
(c) Tropic of Capricorn
(d) Greenwich Meridian
Answer:
(d) Greenwich Meridian

Question 6.
How much time does the earth take to rotate by 1° a longitude?
(a) 2 minutes
(b) 3 minutes
(c) 4 minutes
(d) 6 minutes
Answer:
(c) 4 minutes

Question 7.
How many time zones are there in Canada?
(a) 5
(b) 6
(c) 7
(d) 8
Answer:
(a) 5

Question 8.
What is meant by clock time ?
(a) local time
(b) Visible time
(c) Mean time
(d) International time
Answer:
(c) Mean time

Matching Type Questions

Question 1.
Match column A to column B in the following:

Column A (Line names)	Column B (Line values)
(i) Tropic of Cancer	(a) 66\(\frac { { 1 }^{ \circ  } }{ 2 } \) South latitude
(ii) Equator	(b) 0° Longitude line
(iii) Tropic of capricorn	(c) 66\(\frac { { 1 }^{ \circ  } }{ 2 } \) North latitude
(iv) Greenwich Meridian	(d) 0° latitude line
(v)International date line	(e) 23\(\frac { { 1 }^{ \circ  } }{ 2 } \) North latitude line
(vi) Arctic Circle	(d) 23\(\frac { { 1 }^{ \circ  } }{ 2 } \) South latitude line
(vii) Antarctic Circle	(g) 180° Longitude line

Answers:

1. (c)
2. (d)
3. (f)
4. (b)
5. (g)
6. (c)
7. (a)

Question 2.
Match column A with column B:

Column A (Name of planet)	Column B (Number of satellites)
(i) Autumn Equinox	(a) 21 June
(ii) Summer solstice	(b) 21 March
(iii) Winter solstice	(c) 23 September
(iv) Spring or Vernal Equinox	(d) 22 December

Answers:

1. (c)
2. (a)
3. (d)
4. (b)

RBSE Class 11 Physical Geography Chapter 3 Very Short Answer Type Questions

Question 1.
After the development of civilization, where did human attention turn?
Answer:
After establishing the center of civilization, the attention of human beings turned towards learning more about the surrounding environment, the earth and the sky.

Question 2.
How was the earth considered to be in the beginning?
Answer:
Initially, the Earth was considered stationary, flat or disc – shaped.

Question 3.
How did Aryabhatta describe the earth?
Answer:
Aryabhatta described the earth to be round like a ball and rotating from the west to east direction on its axis, creating night and day.

Question 4.
Who established the central position of the sun?
Answer:
In the 16th century, Astronomers Copernicus and Galileo, established the position of the Sun at the center of the solar system.

Question 5.
Why is earth called oblate spheroid?
Answer:
The earth is round, but its shape is flattened on both poles. Due to the flatness of the Earth’s poles, it is called an oblate spheroid.

Question 6.
Who was the first to determine the perimeter of the Earth?
Answer:
In 256 BC. the Greek scholar, Eratosthenes, had adopted the simplest technique to calculate the perimeter of the Earth, which was almost equal to the current scientific calculation.

Question 7.
What is the Earth’s equatorial and polar diameter?
Answer:
The Earth’s equatorial diameter is 12,756 kilometers while the polar diameter is 12,713 kilometers.

Question 8.
What is the difference between Earth’s equatorial and polar diameter?
Answer:
The difference between the Earth’s equatorial and polar diameter is 43 km.

Question 9.
What is the Earth’s Equatorial and Polar Perimeter?
Answer:
The Earth’s equatorial perimeter is 40,077 kilometers and the polar perimeter is 40,000 kilometers.

Question 10.
What is the difference between the Earth’s equatorial and polar perimeter?
Answer:
A difference of 77 kilometers is found between the Earth’s equatorial and polar perimeter.

Question 11.
What is the total surface area of the Earth?
Answer:
The total area of the Earth is 510 million square kilometers.

Question 12.
What is the terrestrial and oceanic area of the Earth?
Answer:
The terrestrial area of the earth is 149 million square kilometers while the oceanic area is 361 million square kilometers.

Question 13.
What is the volume and density of the Earth?
Answer:
Earth’s volume is 416 million cubic kms, while the Earth’s average density is 5.517 grams per cubic cm.

Question 14.
What are the motions of the earth?
Answer:
There are mainly two motions of the Earth – daily rotational speed and annual revolution speed.

Question 15.
What does the daily or rotational movement mean?
Answer:
The spinning motion of the earth on its axis is called daily or rotational motion. The earth completes one rotation on its axis in 24 hours.

Question 16.
What effect has the impact of centrifugal force made on the earth?
Answer:
Due to the centrifugal force generated by the motion of the Earth, the earth protrudes more on the equatorial region and is flattened on the poles.

Question 17.
What is the Earth’s rotation speed at different latitudes ?
Answer:
Earth’s daily or rotational speed is approximately 1,600 km per hour on the equator, 1,120 km per hour on 45º north and south latitudes, and becomes almost zero on the poles.

Question 18.
Why does the distance of the earth from the Sun vary?
Answer:
The orbit of the Earth is not circular, it is elliptical, due to which the distance between the Sun and the Earth varies.

Question 19.
What is perihelion ?
Answer:
When the sun is at the least distance (147 million km) from the Earth, then such a situation is called the perihelion.

Question 20.
What is the average distance between the sun and the earth?
Answer:
The average distance between Sun and Earth is 150 million kilometers.

Question 21.
What is the maximum and minimum distance between the Sun and the Earth?
Answer:
The maximum distance between Sun and Earth is 152 million kilometers, while the least distance is 147 million kilometers.

Question 22.
When is the state of solstice on the earth?
Answer:
On June 21 and December 22, the Earth has summer and winter solstices respectively.

Question 23.
What does the Spring Equinox mean?
Answer:
On March 21, the sun’s position is on the equator. In this situation, the length of day and night on Earth is almost equal. In the Northern Hemisphere, the spring season starts from. March 21. Hence it is called Spring Equinox.

Question 24.
What is Latitude?
Answer:
The distance measured from the center of the earth to any point on the north or south land surface the equator is called latitude.

Question 25.
What is at longitude?
Answer:
The angular distance between the meridian line passing through any point on earth and the prime meridian line, is the longitude of that point.

Question 26.
What is Tropic of Cancer?
Answer:
The 23\(\frac { { 1 }^{ \circ } }{ 2 } \) North latitude line found in the northern hemisphere is called the Tropic of Cancer.

Question 27.
What is Tropic of Capricorn?
Answer:
The 23\(\frac { { 1 }^{ \circ } }{ 2 } \) South latitude line, which is found in the southern hemisphere, is called the Tropic of Capricorn.

Question 28.
What are the low latitudes?
Answer:
The area between the 23\(\frac { { 1 }^{ \circ } }{ 2 } \) North latitude and 23\(\frac { { 1 }^{ \circ } }{ 2 } \) South latitude on either side of the equator are called low latitudes.

Question 29.
What does the Greenwich meridian mean?
Answer:
The line drawn in north – south direction which passes through Greenwich, located near London, is called the prime meridian or the Greenwich meridian.

Question 30.
What are the great circles?
Answer:
Great circles are those circles which divide the Earth equal regions circles. Their number is 181.

Question 31.
What is local time ?
Answer:
The time of each location according to its longitude is called the local time.

Question 32.
What is the standard time?
Answer:
When the time of a particular place is considered to be the reference for all regions of a country, it is called the standard time of that country.

Question 33.
What is a time zone?
Answer:
The world has been divided into 24 longitudinal sectors to overcome the difference in the local time. Each such sector is called a time zone.

Question 34.
What is meant by is the United States of America been divided into?
Answer:
The United States of America is divided into four time zones, i.e., 75°, 90°, 105° and 120° longitudes.

Question 35.
What is a Solar Day?
Answer:
The duration of time within which a place rotated on the axis comes back to the same position that the sun starts shining up point, it is called a Solar Day.

Question 36.
What is the time equation?
Answer:
Normal solar days are longer and sometimes smaller than mean solar day. The difference in their time is called time Equation.

RBSE Class 11 Physical Geography Chapter 3 Short Answer Type Questions (SA-I)

Question 1.
Discuss the contributions of ancient Indian scholars in the context of earth’s information.
Answer:
In relation to the origin of the Earth, important information is found in Indian texts. In the book ‘Aryabhatiya’ written by Aryabhatta, the earth is said to be spherical. Great Indian astrophysicist Aryabhatta said that the earth is round like a ball and spinning on its axis from west to east direction, creating night and day. Aryabhata and Bhaskaracharya – (II) presented scientific facts about sun and lunar eclipses and gravitation, which could only known to the European people in the 15 – 16th century, A.D.

Question 2.
What is the significance of the axial tilt of the earth?
Answer:
The earth is not at right angles to its axis, but is inclined at 23\(\frac { { 1 }^{ \circ } }{ 2 } \). This 23\(\frac { { 1 }^{ \circ } }{ 2 } \) inclination remains in the same direction during its orbit of the sun. As a result of this inclination of the earth, the north and the south pole come near the sun alternately, resulting in the enjoyment of different seasons in both the hemispheres. If this axial tilt was not there then day and night durations would be equal on earth and it would be impossible to have different seasons.

Question 3.
Into which major parts have the latitudes on earth been divided?
Answer:
0°-90° latitudes are found on the globe from the equator to the north and south poles. These latitudes are divided mainly into the following parts:

1. Low Latitudes:
The lower latitudes are said to be between the 30° North and the 30° South Hemisphere from the equator (0° latitude line).

2. Intermediate latitudes:
The area between 30° – 60° North and South latitudes on the globe are called intermediate latitudes.

3. High Latitude:
The region between 60° – 90° North and South latitudes on the globe are called high latitudes.

Question 4.
What is the meaning of local time? Explain it.
Answer:
The time of each place according to its longitude is called the local time can be determined precisely by the sun’s overhead position. This time the sunlight can tell exactly. The local time is related to the height of the mid – day sun. From this, on the same longitude, all cities in the North – South have the same time. So there is no difference in their local time. The cities located in the East – West will be on different meridian lines. For this reason they will have different times. This is the reason that the local time of the cities located in the East – West have a natural difference. Local time is always in accordance with the midday sunlight.

Question 5.
What was the reason for setting the international date line?
Answer:
The following are the reasons for establishing the International Date Line:

1. When we travel from central or principal meridian towards west or east, we need to set back or take forward our clock by 4 minutes after crossing time. This time line was decided to overcome this problem.
2. After 360° longitudinal transit, 1 day difference was generated. This time line was determined to remove the difference of that 1 day.
3. This date line was considered to be the base reference for beginning of a day, so that day related discrepancy be overcome.
4. The journey from East to West across the international dateline decreases 1 day and travel from west to east across it increases one day. This line was determined to equal this difference.

Question 6.
What change happens when crossing the International Date Line? Explain.
Answer:
The place which is on the west of this line, i.e., towards Asia, if Monday begins for it, then it is the beginning of Sunday for places to its east, i.e., America. When a ship crosses this line and heads towards the United States, they cross the line on Sunday, they will and if they cross this line moving towards Asia, then take out one day from the calendar. That is if cross the line on Sunday, the next day will be Tuesday and not Monday.

Question 7.
Explain the mean time.
Answer:
Mean time:
In daily practice, clocks are often not adjusted ahead of time or behind time. This means that the watches do not show the observable time according to the Sun, but they show the mean – time. Thus, the known time is not taken to be the real time and the duration of the given day is also different. However, if the period of all such days of the year is added and their average is calculated, then the real day period will be detected. This received day is the mean time. The time we use, is based on this. Our watches run according to this mean time. This time it is also called Clock Time.

Question 8.
How is the time equation positive and negative?
Answer:
The speed of the sun is not always the same. It is sometimes affected behind and ahead from the apparent time. If the sun is perpendicularly overhead some time after the clock strikes 12 O’clock then the time equation will be positive (+) and if the sun is shining vertically overhead before the clock shows 12 o’clock, then the time equation is negative (-). Only four dates of the year are such, when the observable time and mean time are the same. These four dates are April 16, June 15, September 1 and December 25. During these dates, the time equation is zero (0).

RBSE Class 11 Physical Geography Chapter 3 Short Answer Type Questions (SA-II)

Question 1.
What is the rotational movement? What are its effects?
Answer:
The rotation of the Earth on its axis is called daily or rotational speed. The earth completes one rotation by rotation of on its axis in 24 hours. The rotation of earth night. This motion of the Earth is from west to east. On the side of the Earth facing the Sun, there is east day and on the other part. Due to the rotation of the Earth from west to east, Sun rises in the east and sets in the west.

Because of the spinning of Earth from west to east, the direction of the spinning of all the constellations and stars remains from east to west direction. Due to this motion of the Earth, there is more protuberance in the equatorial region and on the equator on poles. Apart from this, there is a change in the direction of wind and ocean currents due to this speed. This rotation of the Earth is at approximately 1600 km per hour, at 45° north and south latitude, it is 1,120 km/hr and at poles it becomes almost zero.

Question 2.
Explain Latitude.
Answer:
The equator divides the earth into two equal hemispheres – Northern and Southern Hemisphere. Determination of latitudes is parallel to the equator in the north and south directions. Their angles are determined from the center of the Earth. These Latitude circles become smaller away the equator towards the north and south directions towards the poles. The equator is 0° and the poles are at 90° latitude.

Thus 90° latitude is found in the northern hemisphere and 90° latitude in the southern hemisphere. The distance between any two consecutive latitudes is 111 km, which is slightly higher at very high latitudes due to their flattening on the poles. To get the exact position of a place, the degree is divided into minutes and minutes into seconds. According to the location of a place, its northern latitudes and southern latitudes are determined.

Question 3.
Describe the features of longitudinal lines.
Answer:
Longitudes are the angular lines drawn in north – south direction on the globe. They have the following characteristics:

1. The longest distance between the longitudes is on the equator.
2. On moving towards the poles from the equator, the distance between longitudes decreases.
3. All the longitudes on the poles.
4. Distance between latitudes on the equator is 111 km, on 30° north and south latitudes 96.5 km, on 60° north and south latitudes it is 55.4 km, and on 80° north and south latitudes it is 19.3 km and at 90° north and south latitude, it is zero.
5. There is a difference of 4 minutes on each longitude.
6. All 360° longitude lines when convert into a circle, they become greater circles.

Question 4.
What is the significance of time zone ?
Answer:
If a country is large in the east – west expanse, then keeping a single standard time for the entire nation cannot work, because in such countries, the place located in the east and the the place located in extreme west may have a difference of 4 – 5 hours. In countries like Canada and the,United States, this difference is seen in local time in some places.

Marine vessels also experience great difficulty in remembering the local time of each place. To overcome this inconvenience, the whole earth has been divided into 24 parts. All such parts are called time zones. There is only one standard or mean time in each time zone. These time zones are divided into 24 parts so that each time zone has at difference of one hour.

There are 15° longitudes in each time zone. The number of time zones in different countries can vary according to the nation’s expansion. For example: 5 in Canada, 4 in the United States, 3 in Europe, and 11 times zones in Russia. Due to these time zones, there is a similarity of time in these regions, despite their great expanse.

Question 5.
Explain the equation of time.
Answer:
Equation of time:
The time within which a place is rotated on the axis in one complete rotation and then comes back to the same position, so that the sun begins to shine above it, is called a Solar day. But the Earth’s orbit is not circular, but it is elliptical. At the same time, the position of the Sun is not centered. As a result the earth reaches. When there is winter season in the Northern Hemisphere, then the Earth is relatively close to the Sun, which is called Perihelion.

On the contrary, when it is summer in the northern hemisphere, the Earth is relatively far from the Sun and we call it Aphelion. It is worth noting that the change of the seasons does not depend on the distance of the sun. It is related to the height of the sun’s in sky. i.e. the angular position of the rays obtained and the thermal power obtained from them. When the earth is in a perihelion state, As revolution speed becomes faster. In contrast, the period of Solar – Day (the time between two actual position) decreases – So two types of time are experienced.

Question 6.
What is the observable/apparent time? Explain it.
Answer:
When the sun shines perpendicularly a longitudes, then it is the mid – day time at twelve o’clock in the places located on that line. According to them, the time that the clock keeps at mid-day, then the sun will not be vertical. It will be tilted away from this position because the speed of the sun does not always remain the same.

Due to this variation (decrease – increase), Solar – Day is not convenient for time measurements. Solar – clock is used to know the time through the sun. According to the condition of the sun, we have to take the trouble to keep the time in its accordance, because the clock needles need to be moved forward or backward every day, according to the sun.

RBSE Class 11 Physical Geography Chapter 3 Essay Type Questions

Question 1.
Explain the conditions arising out of the revolution movement of the Earth.
Answer:
Revolution of the Earth:
The second important moment of the Earth is to travel around the Sun in its fixed annual orbit from the west to the east. Earth’s orbit is approximately 965 million km long, which is completed at a speed of approximately 29.6 km per second in 365 days. The orbit of the Earth is not circular but is elliptical, which keeps 4 changing the distance between the Sun and the Earth during the revolution. The average distance between Earth and Sun is 150 million km.

When the earth is at the highest distance (152 million km) from the sun, it is called ‘aphelion’ and when it is at the nearest distance (147 million km) it is called perihelion. In the event of the aphelion, the journey of earth is relatively quick. On the contrary, in the case of ‘Perihelion’ it takes more time to travel.

This keeps the solar-day period decreasing and increasing. Different seasons are made possible due to the revolution of the earth. As a result of the change in both the motion and position of the Earth, the distribution of solar energy on the earth is.

Question 2.
Describe the state of the condition of solstices and equinoxes with suitable illustrations.
Answer:
There is always light on one part of the earth and darkness on the other. The line separating the light and dark part is called the ‘circle of Illumination’. Earth is in the state of summer solstice and winter solstice each year on June 21 and December 22 respectively. On 21st June and 22nd December, the horizontal position of the sun is on the Cancer and Capricorn line respectively. This position is formed in both the hemispheres due to the axial tilt of the Earth at 23\(\frac { { 1 }^{ \circ } }{ 2 } \).

On the 21st of June due to the of the Sun on in the northern hemisphere and winter season in the southern hemisphere. On the contrary, on December 22, there is an opposite situation. The perpendicular rays of the Sun occur on the Capricorn line, due to which there is winter season in the northern hemisphere and summer season in the southern hemisphere as sun rays perpendicular incidence on the earth is only between the Cancer and Capricorn lines (23\(\frac { { 1 }^{ \circ } }{ 2 } \) North and 23\(\frac { { 1 }^{ \circ } }{ 2 } \) South latitudes), so these two act as.

Transitions give mobility to the Earth and there is a change in the position of sun, stars and constellations. This change reflects life, for tune and newness on Earth. Many festivals and rituals are celebrated on the transcendences in different countries of the world. In our country, ‘Makar Sankranti has special significance. This change in the form of a festival is celebrated in whole of the country with joy. Sun worship is done and sesame seeds are consumed on this day. brings autumnal and movements have been demonstrated through the illustrations above.

Equinoxes:
On 21st March and 23th September the position of the Sun is perpendicular on the equator. In this condition, the length of day and night on earth is almost equal. In the northern hemisphere begins the spring season from March 21, hence it is called Spring Equinox. On 23rd September, the sun’s arrival in the south of the equator. In this stage, the illumination circle divides the whole earth from pole to the pole in equal parts. Light in the front of the sun and dark in the opposite part. In the equinoxic condition, the sun rises in the east at 6 a.m. and it at almost the same time in the west in the evening.

Question 3.
Explain the position of the international date line.
Answer:
International date line:
Seeing carefully, it will be known that this line is not straight. What is the reason for this? This line does not lie 180° longitude line from its one end to the other end. In many places, there it strays. Because 180° longitude goes through the many islands of the Pacific Ocean which are governed by the same state.

Therefore, if the international date line was also passed above 180° longitude, then somewhere there would be two dates in the same day in one country, which would have resulted in big inconvenience. Therefore, this line has been made along the 180° longitude but with a zigzag as per requirement.

On seeing the picture of the date line it is clear that its first turn is towards the east. In the Bering Straits between Siberia and Alaska it turns from the 180° East longitude and turns to east. To some distance south to this, to avoid the Aleutian islands, this line moves towards the west. Thus, difference of dates exists between Siberia and Alaska.

Suppose if in Siberia it is July 15th, then in Alaska it would only be 14th of July. The 180° long line passes through the middle of an island of Fiji Islands group. Therefore, due to the difference in timing between the two parts of the same island by date line can be quite inconvenient. Thus, in the southern hemisphere, this line makes a detour around Fiji and Toga islands. The date is kept similar to New Zealand in these islands.

RBSE Solutions for Class 11 Geography

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