Selina Textbook Solutions: Geographic Grid: Latitudes and Longitudes | Geography Class 9 ICSE PDF Download

 Page 1


Geographic Grid: Latitudes and Longitudes 
Exercises 
I. Short Answer Questions 
Question 1. 
What is a geographic grid ? 
Answer: 
The network of the latitudes and the longitudes is known as a geographical grid. 
Question 2. 
Who devised the lines of latitude and longitude ? 
Answer: 
Eratosthenes, the Greek philosopher, first time devised the lines of latitude and 
longitude. 
Question 3. 
What are lines of latitude and longitude ? 
Answer: 
The latitudes are the parallel circles with respect to the equator reducing in length 
northwards and southwards and the poles are the points only. On the other hand 
longitudes are equal in length drawn from North Pole to South Pole with their intervals 
reducing towards poles. 
Question 4. 
Mention two characteristics of lines of latitude ? 
Answer: 
(a) The lines of latitude are parallel to the equator. 
(b) The lines of latitude are drawn at an angular distance with respect to the equator. 
Question 5. 
Name the two hemispheres of the earth made by the Equator. 
Answer: 
Northern hemisphere and Southern hemisphere. 
Question 6. 
Express 1° angular distance in kilometres. 
Answer: 
As the circumference or the equator is nearly about 40,000 km. 
So 1° angular distance in km. will be 40,000/360 =111 km. approximately. 
Page 2


Geographic Grid: Latitudes and Longitudes 
Exercises 
I. Short Answer Questions 
Question 1. 
What is a geographic grid ? 
Answer: 
The network of the latitudes and the longitudes is known as a geographical grid. 
Question 2. 
Who devised the lines of latitude and longitude ? 
Answer: 
Eratosthenes, the Greek philosopher, first time devised the lines of latitude and 
longitude. 
Question 3. 
What are lines of latitude and longitude ? 
Answer: 
The latitudes are the parallel circles with respect to the equator reducing in length 
northwards and southwards and the poles are the points only. On the other hand 
longitudes are equal in length drawn from North Pole to South Pole with their intervals 
reducing towards poles. 
Question 4. 
Mention two characteristics of lines of latitude ? 
Answer: 
(a) The lines of latitude are parallel to the equator. 
(b) The lines of latitude are drawn at an angular distance with respect to the equator. 
Question 5. 
Name the two hemispheres of the earth made by the Equator. 
Answer: 
Northern hemisphere and Southern hemisphere. 
Question 6. 
Express 1° angular distance in kilometres. 
Answer: 
As the circumference or the equator is nearly about 40,000 km. 
So 1° angular distance in km. will be 40,000/360 =111 km. approximately. 
Question 7. 
Name the thermal zones of the earth. 
Answer: 
The thermal zones of the earth are Tropical, Temperate and Polar zones. 
Question 8. 
With the help of degrees, name the important lines of latitude. 
Answer: 
(a) Tropic of Cancer — 23 1/2°N 
(b) Tropic of Capricorn — 23 1/2° S. 
(c) Arctic Circle — 66 1/2° N. 
(d) Antarctic Circle — 66 1/2° S 
(e) North Pole — 90°N 
(f) South Pole — 90°S 
Question 9. 
Which temperature zone receives almost vertical rays of the sun and which zones 
receive slanting rays ? 
Answer: 
The Tropical zone gets vertical rays of the sun, while temperate and polar zones receive 
slanting rays of the sun. 
Question 10. 
Which line is known as the Prime Meridian ? State its importance. 
Answer: 
Greenwich Meridian is called the ‘Prime Meridian’ or the 0° longitude. The time is 
calculated with respect to this Meridian. So it is the basic Meridian and time is written as 
G.M.T. (Greenwich Meridian Time) The earth takes 4 minutes for moving 1° distance. 
Question 11. 
How can the general climate of an area be described with the help of the lines of 
latitudes ? 
Answer: 
The temperature decreases northwards and southwards from the equator. The region 
within 23 1/2° N and 23 1/2° S will get tropical climate with ample temperature and 
rainfall. On the other hand the regions between 
23 1/2° N – 66 1/2° N and 23 1/2° S – 66 1/2° S will get temperate climate, while the 
regions known as Arctic and Antarctic circles get very cold polar climate as Tundra 
region. 
 
Page 3


Geographic Grid: Latitudes and Longitudes 
Exercises 
I. Short Answer Questions 
Question 1. 
What is a geographic grid ? 
Answer: 
The network of the latitudes and the longitudes is known as a geographical grid. 
Question 2. 
Who devised the lines of latitude and longitude ? 
Answer: 
Eratosthenes, the Greek philosopher, first time devised the lines of latitude and 
longitude. 
Question 3. 
What are lines of latitude and longitude ? 
Answer: 
The latitudes are the parallel circles with respect to the equator reducing in length 
northwards and southwards and the poles are the points only. On the other hand 
longitudes are equal in length drawn from North Pole to South Pole with their intervals 
reducing towards poles. 
Question 4. 
Mention two characteristics of lines of latitude ? 
Answer: 
(a) The lines of latitude are parallel to the equator. 
(b) The lines of latitude are drawn at an angular distance with respect to the equator. 
Question 5. 
Name the two hemispheres of the earth made by the Equator. 
Answer: 
Northern hemisphere and Southern hemisphere. 
Question 6. 
Express 1° angular distance in kilometres. 
Answer: 
As the circumference or the equator is nearly about 40,000 km. 
So 1° angular distance in km. will be 40,000/360 =111 km. approximately. 
Question 7. 
Name the thermal zones of the earth. 
Answer: 
The thermal zones of the earth are Tropical, Temperate and Polar zones. 
Question 8. 
With the help of degrees, name the important lines of latitude. 
Answer: 
(a) Tropic of Cancer — 23 1/2°N 
(b) Tropic of Capricorn — 23 1/2° S. 
(c) Arctic Circle — 66 1/2° N. 
(d) Antarctic Circle — 66 1/2° S 
(e) North Pole — 90°N 
(f) South Pole — 90°S 
Question 9. 
Which temperature zone receives almost vertical rays of the sun and which zones 
receive slanting rays ? 
Answer: 
The Tropical zone gets vertical rays of the sun, while temperate and polar zones receive 
slanting rays of the sun. 
Question 10. 
Which line is known as the Prime Meridian ? State its importance. 
Answer: 
Greenwich Meridian is called the ‘Prime Meridian’ or the 0° longitude. The time is 
calculated with respect to this Meridian. So it is the basic Meridian and time is written as 
G.M.T. (Greenwich Meridian Time) The earth takes 4 minutes for moving 1° distance. 
Question 11. 
How can the general climate of an area be described with the help of the lines of 
latitudes ? 
Answer: 
The temperature decreases northwards and southwards from the equator. The region 
within 23 1/2° N and 23 1/2° S will get tropical climate with ample temperature and 
rainfall. On the other hand the regions between 
23 1/2° N – 66 1/2° N and 23 1/2° S – 66 1/2° S will get temperate climate, while the 
regions known as Arctic and Antarctic circles get very cold polar climate as Tundra 
region. 
 
Question 12. 
Which line of longitude is used to fix the World Standard Time ? State its value in 
degrees. 
Answer: 
Greenwich Meridian is used to fix the World Standard Time. Its value in degrees is 0°. 
This time is written as G.M.T. 
Question 13. 
State the longitudinal value in degrees of Indian Standard Meridian. 
Answer: 
Longitudinal value of Indian Standard Meridian is 82 1/2° E. It passes midway through 
India nearly along the city of Allahabad. 
Question 14. 
What is meant by IDL ? State its importance. 
Answer: 
IDL means the International Date Line, which is along 180° E & W. The date or day 
changes while crossing this line i.e. while there is Monday in the Eastern Hemisphere 
i.e. 
0° – 180°E, there will be Sunday in the Western Hemisphere i. e. 0° – 180° W. 
Question 15. 
What are the Great Circle Routes ? State their importance. 
Answer: 
The Great Circle Routes follow the great circles i. e. the perimeters of the earth, which 
cover the shortest distances between any two places in spite of the zigzag routes along 
the surface of earth. These circles are beneficial for following the shortest distances 
between any two places and help in saving the time. 
i. e. the shortest routes are covered in minimum time span. 
Question 16. 
What is a globe ? State the importance of a globe. 
Answer: 
A globe is a man-made spherical model of the earth. A globe is very useful model to 
display the actual shape of the earth with its tilted axis ; The rotation and revolution of 
the earth can be very clearly shown by it along with the continents and oceans. 
II. Give reasons for each of the following 
Question 1. 
Lines of latitude carve out the heat zones of the earth. 
Answer: 
The Temperature goes on decreasing from the equator towards the poles. So the 
Page 4


Geographic Grid: Latitudes and Longitudes 
Exercises 
I. Short Answer Questions 
Question 1. 
What is a geographic grid ? 
Answer: 
The network of the latitudes and the longitudes is known as a geographical grid. 
Question 2. 
Who devised the lines of latitude and longitude ? 
Answer: 
Eratosthenes, the Greek philosopher, first time devised the lines of latitude and 
longitude. 
Question 3. 
What are lines of latitude and longitude ? 
Answer: 
The latitudes are the parallel circles with respect to the equator reducing in length 
northwards and southwards and the poles are the points only. On the other hand 
longitudes are equal in length drawn from North Pole to South Pole with their intervals 
reducing towards poles. 
Question 4. 
Mention two characteristics of lines of latitude ? 
Answer: 
(a) The lines of latitude are parallel to the equator. 
(b) The lines of latitude are drawn at an angular distance with respect to the equator. 
Question 5. 
Name the two hemispheres of the earth made by the Equator. 
Answer: 
Northern hemisphere and Southern hemisphere. 
Question 6. 
Express 1° angular distance in kilometres. 
Answer: 
As the circumference or the equator is nearly about 40,000 km. 
So 1° angular distance in km. will be 40,000/360 =111 km. approximately. 
Question 7. 
Name the thermal zones of the earth. 
Answer: 
The thermal zones of the earth are Tropical, Temperate and Polar zones. 
Question 8. 
With the help of degrees, name the important lines of latitude. 
Answer: 
(a) Tropic of Cancer — 23 1/2°N 
(b) Tropic of Capricorn — 23 1/2° S. 
(c) Arctic Circle — 66 1/2° N. 
(d) Antarctic Circle — 66 1/2° S 
(e) North Pole — 90°N 
(f) South Pole — 90°S 
Question 9. 
Which temperature zone receives almost vertical rays of the sun and which zones 
receive slanting rays ? 
Answer: 
The Tropical zone gets vertical rays of the sun, while temperate and polar zones receive 
slanting rays of the sun. 
Question 10. 
Which line is known as the Prime Meridian ? State its importance. 
Answer: 
Greenwich Meridian is called the ‘Prime Meridian’ or the 0° longitude. The time is 
calculated with respect to this Meridian. So it is the basic Meridian and time is written as 
G.M.T. (Greenwich Meridian Time) The earth takes 4 minutes for moving 1° distance. 
Question 11. 
How can the general climate of an area be described with the help of the lines of 
latitudes ? 
Answer: 
The temperature decreases northwards and southwards from the equator. The region 
within 23 1/2° N and 23 1/2° S will get tropical climate with ample temperature and 
rainfall. On the other hand the regions between 
23 1/2° N – 66 1/2° N and 23 1/2° S – 66 1/2° S will get temperate climate, while the 
regions known as Arctic and Antarctic circles get very cold polar climate as Tundra 
region. 
 
Question 12. 
Which line of longitude is used to fix the World Standard Time ? State its value in 
degrees. 
Answer: 
Greenwich Meridian is used to fix the World Standard Time. Its value in degrees is 0°. 
This time is written as G.M.T. 
Question 13. 
State the longitudinal value in degrees of Indian Standard Meridian. 
Answer: 
Longitudinal value of Indian Standard Meridian is 82 1/2° E. It passes midway through 
India nearly along the city of Allahabad. 
Question 14. 
What is meant by IDL ? State its importance. 
Answer: 
IDL means the International Date Line, which is along 180° E & W. The date or day 
changes while crossing this line i.e. while there is Monday in the Eastern Hemisphere 
i.e. 
0° – 180°E, there will be Sunday in the Western Hemisphere i. e. 0° – 180° W. 
Question 15. 
What are the Great Circle Routes ? State their importance. 
Answer: 
The Great Circle Routes follow the great circles i. e. the perimeters of the earth, which 
cover the shortest distances between any two places in spite of the zigzag routes along 
the surface of earth. These circles are beneficial for following the shortest distances 
between any two places and help in saving the time. 
i. e. the shortest routes are covered in minimum time span. 
Question 16. 
What is a globe ? State the importance of a globe. 
Answer: 
A globe is a man-made spherical model of the earth. A globe is very useful model to 
display the actual shape of the earth with its tilted axis ; The rotation and revolution of 
the earth can be very clearly shown by it along with the continents and oceans. 
II. Give reasons for each of the following 
Question 1. 
Lines of latitude carve out the heat zones of the earth. 
Answer: 
The Temperature goes on decreasing from the equator towards the poles. So the 
latitudinal zones are the actual heat zones of the earth, namely tropical, temperate and 
polar zones. 
Question 2. 
Lines of longitude are also called Meridians of longitude? 
Answer: 
The word ‘meridian’ means related to noon or 12 p.m. As every longitude receives the 
noon time or 12 p.m. at different intervals where the sun’s rays are exactly vertical over 
a particular longitude. On a particular longitude the noon-time is the same from north to 
south ; so a longitude is also called a Meridians of longitude. 
Question 3. 
Diametrically opposite lines of longitude and the Equator are called Great Circles. 
Answer: 
Every longitude along with its opposite longitude makes a complete circle around the 
earth and another complete big circle is the equator; while the latitudes make smaller 
circles along with the poles to be only points. So the equator and the longitudinal lines 
around the earth are called the Great Circles. 
Question 4. 
The Greenwich time is called Greenwich Mean Time. 
Answer: 
The time of any place or country is calculated according to the 0° longitude or 
Greenwich meridian, the time change is of 4 minutes for every 0° longitude. So it is 
called Greenwich Mean Time. 
Question 5. 
IDL deviates and goes zig-zag near some Islands in the Pacific ocean. 
Answer: 
IDL is not a straight line, but it deviates in order to classify some scattered Islands in a 
particular divisions of Hemispheres, so that the day and time can be calculated 
according to the line, as the natural position of the Islands is haphazard. 
Question 6. 
A globe is the most popular model of the earth. 
Answer: 
As our earth is spherical in shape, so it can be best represented by a spherical model 
like a globe. A globe illustrates the position of continents and oceans, the tilted axis of 
the earth, its rotation, the sea and air routes etc. So a globe is a perfect model of the 
earth. 
 
 
Page 5


Geographic Grid: Latitudes and Longitudes 
Exercises 
I. Short Answer Questions 
Question 1. 
What is a geographic grid ? 
Answer: 
The network of the latitudes and the longitudes is known as a geographical grid. 
Question 2. 
Who devised the lines of latitude and longitude ? 
Answer: 
Eratosthenes, the Greek philosopher, first time devised the lines of latitude and 
longitude. 
Question 3. 
What are lines of latitude and longitude ? 
Answer: 
The latitudes are the parallel circles with respect to the equator reducing in length 
northwards and southwards and the poles are the points only. On the other hand 
longitudes are equal in length drawn from North Pole to South Pole with their intervals 
reducing towards poles. 
Question 4. 
Mention two characteristics of lines of latitude ? 
Answer: 
(a) The lines of latitude are parallel to the equator. 
(b) The lines of latitude are drawn at an angular distance with respect to the equator. 
Question 5. 
Name the two hemispheres of the earth made by the Equator. 
Answer: 
Northern hemisphere and Southern hemisphere. 
Question 6. 
Express 1° angular distance in kilometres. 
Answer: 
As the circumference or the equator is nearly about 40,000 km. 
So 1° angular distance in km. will be 40,000/360 =111 km. approximately. 
Question 7. 
Name the thermal zones of the earth. 
Answer: 
The thermal zones of the earth are Tropical, Temperate and Polar zones. 
Question 8. 
With the help of degrees, name the important lines of latitude. 
Answer: 
(a) Tropic of Cancer — 23 1/2°N 
(b) Tropic of Capricorn — 23 1/2° S. 
(c) Arctic Circle — 66 1/2° N. 
(d) Antarctic Circle — 66 1/2° S 
(e) North Pole — 90°N 
(f) South Pole — 90°S 
Question 9. 
Which temperature zone receives almost vertical rays of the sun and which zones 
receive slanting rays ? 
Answer: 
The Tropical zone gets vertical rays of the sun, while temperate and polar zones receive 
slanting rays of the sun. 
Question 10. 
Which line is known as the Prime Meridian ? State its importance. 
Answer: 
Greenwich Meridian is called the ‘Prime Meridian’ or the 0° longitude. The time is 
calculated with respect to this Meridian. So it is the basic Meridian and time is written as 
G.M.T. (Greenwich Meridian Time) The earth takes 4 minutes for moving 1° distance. 
Question 11. 
How can the general climate of an area be described with the help of the lines of 
latitudes ? 
Answer: 
The temperature decreases northwards and southwards from the equator. The region 
within 23 1/2° N and 23 1/2° S will get tropical climate with ample temperature and 
rainfall. On the other hand the regions between 
23 1/2° N – 66 1/2° N and 23 1/2° S – 66 1/2° S will get temperate climate, while the 
regions known as Arctic and Antarctic circles get very cold polar climate as Tundra 
region. 
 
Question 12. 
Which line of longitude is used to fix the World Standard Time ? State its value in 
degrees. 
Answer: 
Greenwich Meridian is used to fix the World Standard Time. Its value in degrees is 0°. 
This time is written as G.M.T. 
Question 13. 
State the longitudinal value in degrees of Indian Standard Meridian. 
Answer: 
Longitudinal value of Indian Standard Meridian is 82 1/2° E. It passes midway through 
India nearly along the city of Allahabad. 
Question 14. 
What is meant by IDL ? State its importance. 
Answer: 
IDL means the International Date Line, which is along 180° E & W. The date or day 
changes while crossing this line i.e. while there is Monday in the Eastern Hemisphere 
i.e. 
0° – 180°E, there will be Sunday in the Western Hemisphere i. e. 0° – 180° W. 
Question 15. 
What are the Great Circle Routes ? State their importance. 
Answer: 
The Great Circle Routes follow the great circles i. e. the perimeters of the earth, which 
cover the shortest distances between any two places in spite of the zigzag routes along 
the surface of earth. These circles are beneficial for following the shortest distances 
between any two places and help in saving the time. 
i. e. the shortest routes are covered in minimum time span. 
Question 16. 
What is a globe ? State the importance of a globe. 
Answer: 
A globe is a man-made spherical model of the earth. A globe is very useful model to 
display the actual shape of the earth with its tilted axis ; The rotation and revolution of 
the earth can be very clearly shown by it along with the continents and oceans. 
II. Give reasons for each of the following 
Question 1. 
Lines of latitude carve out the heat zones of the earth. 
Answer: 
The Temperature goes on decreasing from the equator towards the poles. So the 
latitudinal zones are the actual heat zones of the earth, namely tropical, temperate and 
polar zones. 
Question 2. 
Lines of longitude are also called Meridians of longitude? 
Answer: 
The word ‘meridian’ means related to noon or 12 p.m. As every longitude receives the 
noon time or 12 p.m. at different intervals where the sun’s rays are exactly vertical over 
a particular longitude. On a particular longitude the noon-time is the same from north to 
south ; so a longitude is also called a Meridians of longitude. 
Question 3. 
Diametrically opposite lines of longitude and the Equator are called Great Circles. 
Answer: 
Every longitude along with its opposite longitude makes a complete circle around the 
earth and another complete big circle is the equator; while the latitudes make smaller 
circles along with the poles to be only points. So the equator and the longitudinal lines 
around the earth are called the Great Circles. 
Question 4. 
The Greenwich time is called Greenwich Mean Time. 
Answer: 
The time of any place or country is calculated according to the 0° longitude or 
Greenwich meridian, the time change is of 4 minutes for every 0° longitude. So it is 
called Greenwich Mean Time. 
Question 5. 
IDL deviates and goes zig-zag near some Islands in the Pacific ocean. 
Answer: 
IDL is not a straight line, but it deviates in order to classify some scattered Islands in a 
particular divisions of Hemispheres, so that the day and time can be calculated 
according to the line, as the natural position of the Islands is haphazard. 
Question 6. 
A globe is the most popular model of the earth. 
Answer: 
As our earth is spherical in shape, so it can be best represented by a spherical model 
like a globe. A globe illustrates the position of continents and oceans, the tilted axis of 
the earth, its rotation, the sea and air routes etc. So a globe is a perfect model of the 
earth. 
 
 
III. Long Answer Questions  
Question 1. 
Describe the lines of latitude, their importance and use. 
Answer: 
The face of the earth is divided into various parallel circles with respect to the equator 
on both sides at different angular distances. These lines are veiy important to decide the 
climate and temperature range of any place or region as the temperature goes on 
decreasing from the equator to polewards. 
Question 2. 
With reference to the International Date Line, state the following: 
(a) It is meaning and application. 
(b) The important deviations it makes and reasons for the same. 
(c) Give an example of how time lost or gained is computed with reference to this line. 
Answer: 
(a) The time and date changes as we cross the International Date Line i.e. the 
navigators or pilots have to loose one day while crossing westwards and gain one day 
while crossing eastwards i.e. When one travels from Tokyo to San Francisco on 
Monday, he will reach San Francisco on Sunday. 
(b) The International Date Line is not a straight line but have some deviations in order to 
adjust with the pattern of the landforms and some islands to decide for the time and 
date of these places and regions. 
(c) If we are moving from Hawaii Islands towards Shanghai on Tuesday, we will reach 
there on Wednesday or Thursday probably, but if we are going eastwards from Shangai 
to Hawaii islands on Tuesday. We may reach there either on Tuesday or Monday. 
Question 3. 
Describe the lines of longitude and state their use in relation to distance and time. 
Answer: 
A longitude is the angular distance of a place east or we§t of the Prime Meridian or 0° 
longitude. 
The lines of longitude are the great semi-circles joining North pole and South pole and 
are equal in length. These are 0° – 180°E and 0° – 180°W longitudes or total 360°. As 
the earth takes 24 hours to make a complete rotation along its axis crossing 360° lines 
of longitude, so earth takes nearly 4 minutes to move one degree (1 °) longitude or 111 
km length or distance. There is difference of time of one hour between 15° interval of 
longitudes. According to the clock-time, EGA stands for East-Gain-Add and WLS means 
West Lose Subtract. In other words for each 10 longitude towards east 4 minutes are to 
be added and towards west for each 1° longitude 4 minutes are to be subtracted.