# Latitudes and Longitudes

## Answer the following questions briefly

#### Question 1

Why do we need to locate places on Earth?

We need to locate places on earth because:

1. It helps us to know the exact position of places.
2. It helps to find distance between two places if their exact positions are located.
3. It gives us an idea to locate physical features, villages, cities etc.
4. Finding location helps us to design various infrastructures like roads, railways.

#### Question 2

What do you mean by the latitude of a place?

The latitude of a place is the angular distance of that place North or South of the equator, as measured from the centre of the earth.

#### Question 3

What is meant by Prime Meridian?

The 0° longitude passing through Greenwich near London is called the Prime meridian.

#### Question 4

Explain why there is no higher latitude other than 90 degrees North and South.

There is no higher latitude other than 90 degrees North and South because lines of latitude start at 0° (equator) and end at 90° (poles). All planes make a maximum angle of 90° from the plane of the equator.

#### Question 5

Explain why Lines of Longitudes are called Meridian of Longitude.

The Lines of Longitudes are called Meridian of Longitude because the word 'meridian' means "midday" and all the places on the same meridian have their noon at the same time.

#### Question 6

State two properties of the Lines of Latitude.

Two properties of the Lines of Latitude are:

1. Each latitude is an imaginary circle parallel to the equator and centered on the polar axis.
2. The radius and the length of parallels gradually decrease from its maxima at the equator to its minima at the poles.

#### Question 7

State two properties of Lines of Longitude.

Two properties of Lines of Longitude are:

1. All meridians are complete circles dividing the earth into Eastern and Western Hemisphere.
2. The longitudes are drawn 1° apart on the Equator, with 1° to 179° towards east and 1° to 179° towards west.

#### Question 8

The distance between two successive parallels of latitudes is 111 km. Explain.

The whole earth represents 360° and the circumference of the earth is approximately 40,000 km. Therefore, for each degree i.e. the difference between two latitudes is 111km (i.e 40000 divided by 360).

#### Question 9

What are the limits of two Temperate Zones?

The limit of northern temperate zone is 23 1/2°N to 66 1/2°N and the limit of southern temperate zone is 23 1/2°S to 66 1/2°S. The temperate zone stretches from Torrid zone to Frigid zone.

#### Question 10

Why are the places in the Torrid Zone hotter than those in other zones?

The Torrid zone or the tropical zones lie between the Tropic of cancer and Tropic of Capricorn which mark the limit of the overhead Sun to North and South of the Equator, i.e., 23 1/2°N to 23 1/2°S. This area receives direct sun rays and therefore, the places in the Torrid Zone are hotter than those in other zones.

#### Question 11

Why are the places in the Frigid Zone colder than in other zones?

The Frigid Zone experiences colder temperatures compared to other zones due to the inclination of the earth's axis, which results in the area receiving oblique rays of sunlight during the winter.

#### Question 12

How is the Local Time of a place fixed?

The Local Time of a place is fixed according to the central meridian of its country. When the sun is overhead on the central meridian it is 12 o'clock noon at that place. For example, the central meridian of India is 82 1/2° E and passes through Allahabad and it is the standard time line for the whole country.

#### Question 13

Is it correct to say that Local Time is the Sun Time?

Yes, it is correct to say that Local Time is the Sun Time because local time is determined based on Sun's apparent movement.

#### Question 14

If the GMT at 0° longitude is 12 noon, find the local time of place A (30°E).

The difference in longitude between 0° and place A is 30° towards east.

Since, for every 1° difference in longitude the difference of time is 4 minutes.

Therefore, the local time of place A will be 30 x 4 = 120 minutes = 2hrs.

As, A is located to the east, it will be 2 hours ahead of Greenwich time: 12 + 2 = 14hr or 2 pm.

Therefore time at place A will be 2 pm.

#### Question 15

Why is the Standard Time considered necessary?

The Standard Time is considered necessary because if every city had to keep the time of their own meridian, there would have been much difference in the local time of one city and the other. This would have led to a lot of confusion.

#### Question 16

What are Time Zones? How many Time Zones do we have?

A zone on terrestrial globe that is approximately 15° longitude wide with 1 hour difference in time from other zone, is called time zone. The world is divided into 24 time zones and India has one time zone.

#### Question 17

London experiences a lower temperature than Singapore throughout the year. Why?

Singapore is situated in torrid zone, near the equator while London is located in temperate zone. Torrid zone receives direct sun rays and is hotter than the temperate zone which receives slant rays of the sun. Therefore, London experiences a lower temperature than Singapore throughout the year.

#### Question 18

What is International Date Line? Describe the use of this line.

A zigzag line at roughly 180° meridian is the line which is internationally adopted as International Date Line or IDL. On either side of this line, a difference of whole day is observed. This is because the earth completes one rotation on its axis in 24 hours as it rotates from west to east.

International Date Line is for the convenience of those travelling round the world in order to avoid any confusion.

#### Question 19

Why do some countries have many Time Zones?

Some countries have large longitudinal extent and therefore they have many tine zones.

#### Question 20

What are Small Circles?

The 0° latitude that circumscribes the earth around it's centre is called Equator or the great circle and all other circles that do not circumscribes the earth around it's centre are called small circles.

#### Question 21

Except for the Equator, other Parallels of Latitudes are not Great Circles. Why?

The equator is the only latitude that circumscribes the earth around it's centre and therefore it is the largest latitude. All other latitudes, either in north or in south, are smaller than equator because they do not circumscribe the earth around its centre.

#### Question 22

How is the use of local time inconvenient in practical life?

The use of local time is inconvenient in practical life because local time is different in different countries. For those travelling abroad, it is very confusing to have different time zones.

#### Question 23

What is a Grid?

A grid is a network of evenly spaced horizontal and vertical lines used to identify locations on a map. Earth's grid refers to the network of latitudes and longitudes on the earth's surface.

#### Question 24

Who was the first mathematician to have measured the circumference of the Earth?

The first mathematician to have measured the circumference of the Earth was Eratosthenes.

#### Question 25

Name the important Climatic Zones of the World.

The important Climatic Zones of the World are:

1. The Torrid or tropical zones
2. Temperate zones
3. Frigid zones

#### Question 26

State the rate of change of time with longitude.

For every 1° change in longitude, the change in time is 4 minutes.

#### Question 27

Explain how latitudes and longitudes help to locate position of a place on a globe.

The latitudes and longitudes are horizontal and vertical lines which form a grid on the globe or map. We can easily locate a place on the globe if we have its longitudinal and latitudinal positions. The point of intersection of its latitude and longitude will determine the position of that place on globe.

#### Question 28

Answer the following questions based on the below diagram:

1. What does PP' represent?
2. What does TT' represent?
3. What is the latitude of the place X?

1. Latitude
2. Longitude
3. 40° N

#### Question 29

Distinguish between:

1. Local Time and standard Time
2. Parallels and Meridians
3. Equator and Prime Meridian

1. Difference between Local Time and Standard Time:
S.
No.
Local TimeStandard Time
1.Local time of a place can be calculated if we know the longitude of the place.Local time of a country's central meridian is the standard time of the country.
2..Local time changes with longitude.It remains same within a country.
1. Difference between Parallels and Meridians:
S.
No.
ParallelsMeridians
1.They are the imaginary circles parallel to the equator.These are the imaginary lines running from the north pole to the south pole.
2.They never intersect each other.They intersect at north and south pole.
3.They are also known as latitudes.They are also known as longitudes.
4.They vary in length.They have same length.
1. Difference between Equator and Prime Meridian:
S.
No.
EquatorPrime Meridian
1.It is the latitude of 0° that circumscribes the earth around its centre.It is the longitude of 0° which passes through Greenwich near London.
2.It divides the earth into Southern and Northern hemisphere.It divides the earth into Eastern and Western hemisphere.

## Define the following terms

#### Question 1

Latitude

The latitude of a place is the angular distance of that place North or South of the equator, as measured from the centre of the earth.

#### Question 2

Longitude

The longitude of a place is the angular distance of that place east or west of the prime meridian.

#### Question 3

Meridian

The imaginary lines or semi-circles that connect north pole and south pole are called meridian.

#### Question 4

Prime Meridian

Prime Meridian is the longitude of 0° which connects north and south poles and passes through Greenwich near London.

#### Question 5

Local time

When the sun is overhead at a place, the local time is 12 o'clock noon at that place. Local time of a place can also be calculated if we know the longitude of the place.

#### Question 6

Standard time

Standard time of a country is defined as the local time of its central meridian which is observed throughout the country.

#### Question 7

Indian Standard Time

The longitude of 82 1/2°E is the central meridian of India which passes through Allahabad. Its local time is the standard time for the country and is known as Indian Standard Time.

#### Question 8

Greenwich Mean Time

The local time of zero degree meridian which passes through the Royal Astronomical Observatory at Greenwich, is taken as international standard time and is known as Greenwich Mean Time.

#### Question 9

International Date Line

The longitude at 180° is considered as International Date Line as on either side of this line, a difference of one whole day is observed.

#### Question 10

Great circle

The latitude at 0° which circumscribe the earth around it's centre and divides the earth into two hemispheres is called Great circle.

#### Question 11

Small circle

All other latitudes except the equator are smaller (than the equator) and are known as Small circles.

#### Question 12

Grid

A grid is a network of evenly spaced horizontal lines (latitudes) and vertical lines (longitudes) used to identify locations on a map.

## Distinguish between the following pairs

#### Question 1

Latitude and Longitude.

S.
No.
LatitudeLongitude
1.It is the angular distance of a point, north or south of the equator, as measured in degrees.It is the angular distance along the equator measured in degrees. It is measured east or west of Greenwich 0° to 180°.
2.All latitudes are parallel to the equator.All meridians of longitude converge at the poles.
3.The distance between two latitudes is approximately 111 km throughout.The distance between two longitudes is maximum at the equator and goes on decreasing as one goes towards the poles.
4.There are 90° of latitudes in the north and 90° latitudes south of the equator.There are 360° of longitude, 180° each in east and west of the Prime Meridian.
5.The latitudes from equator to poles are used to demarcate temperature zones.The longitudes are used to determine the time with reference to the time at Prime Meridian (GMT).

#### Question 2

Great Circle and Small Circle

S.
No.
Great CircleSmall Circle
1.The 0° latitude is known as Great Circle.All other latitudes except the Great circle are Small circles.
2.It is also known as equator.They are also known as parallels of Latitude.

#### Question 3

Greenwich Mean Time and Indian Standard Time

S.
No.
Greenwich Mean TimeIndian Standard Time
1.The local time of zero degree meridian which passes through the Royal Astronomical Observatory at Greenwich, is known as Greenwich Mean Time.The longitude of 82 1/2°E is the central meridian of India which passes through Allahabad. Its local time is known as Indian Standard Time.
2.It is taken as International Standard Time.Its local time is the standard time for India.

## Give reasons for the following

#### Question 1

Latitudes and Longitudes are always expressed in angles.

Latitudes and Longitudes are always expressed in angles because they represent angular distance as the earth is spherical in shape.

#### Question 2

Large countries have many time zones.

Large countries have larger longitudinal extent and therefore they have many time zones. For example, Canada has 6 time zones.

#### Question 3

The international Date Line is not a straight line like other longitudes.

The International Date Line is not a straight line like other longitudes because in order to avoid any landmass, deviation has been taken. It is done to avoid the confusion of having different dates in the same country.

#### Question 4

A person gains time as he travels towards east.

A person gains time as he travels towards east because the earth rotates from west to east. Places on the east of a given point on the earth are ahead of time.

#### Question 5

The intervals between successive parallels are constant.

The intervals between successive parallels are constant because the latitudes are parallel and equidistant to each other.

#### Question 6

A person travelling from Mumbai to London has to alter his watch.

A person travelling from Mumbai to London has to alter his watch because both the cities are in different time zones.

#### Question 7

The difference between I.S.T. and the G.M.T. is 5 hours and 30 minutes.

The difference between longitudes of I.S.T. and the G.M.T. = 82 1/2°

Since, the difference of 1° in longitude = a difference of 4 minutes

Therefore, for difference of 82 1/2°, the difference in time = 4 x 82 1/2 = 330 minutes = 5 hrs 30 min.

#### Question 8

Parallels are not equal in length.

Since shape of the Earth is an oblate spheroid, the radius and length of parallels gradually decrease from its maxima at the Equator to its minima at the Poles. Hence, parallels are not equal in length.

#### Question 9

Navigators use Great circle route for navigation.

Navigators use Great circle route for navigation because Great circle routes are the shortest distance between the two places on the Earth. They help to save fuel and time so they are very economical.

## Draw a neat diagram to show the following

#### Question 1

Parallels of Latitude

Below diagram shows Parallels of Latitude:

#### Question 2

Temperature Zones

Below diagram shows Temperature Zones:

#### Question 3

Earth's Grid

Below diagram shows Earth's Grid:

## Choose the correct option

#### Question 1

Earth is divided into Northern & Southern Hemisphere by which of the following imaginary line?

1. Prime Meridian
2. Tropic of Cancer
3. Equator
4. International Date Line

Equator

#### Question 2

What is the latitude of Arctic Circle?

1. 66 1⁄2°S
2. 23 1⁄2°S
3. 66 1⁄2°N
4. 23 1⁄2°N

66 1⁄2°N

#### Question 3

How many total lines of latitudes are there in the world?

1. 90
2. 91
3. 180
4. 181

181

#### Question 4

Refer to the image and identify the climatic zone of the shaded region.

1. North Frigid Zone
2. North Temperate Zone
3. Torrid Zone
4. South Frigid Zone

Torrid Zone

#### Question 5

There is a time difference of ............... for every 1° of longitudinal difference.

1. 2 minutes
2. 4 minutes
3. 1 hour
4. 60 seconds

4 minutes

#### Question 6

What is the full form of IDL?

1. International Diagonal line
2. Internal Detour Line
3. International Date Line
4. Intermediate Diagonal Line

International Date Line

#### Question 7

Which of the following meridian is called the Central Meridian of India?

1. 83 1⁄2°W
2. 82 1⁄2°E
3. 72°E

82 1⁄2°E

#### Question 8

USA has ............... time zones.

1. 8
2. 11
3. 6
4. 7

6

#### Question 9

Which of the following statements related to lines of latitude is not correct?

1. They are called parallels of Latitude.
2. They are used to determine time.
3. They are important to determine climate.
4. Equator is the largest line of latitude.

They are used to determine time

Meridian means

1. Midnight
2. Midday
3. Morning
4. Dusk

Midday

#### Question 11

The difference between IST & GMT is

1. 6 hours
2. 4 hours 30 minutes
3. 5 hours 30 mins
4. 12 hours

5 hours 30 mins

#### Question 12

Which of the following statement about Great circle is true?

1. All the parallels are Great circles.
2. Navigators find it difficult to follow the route of Great circle.
3. Equator & all the meridians are Great circles.
4. All the above.

Equator & all the meridians are Great circles.

#### Question 13

World is divided into ............... time zones.

1. 20
2. 5
3. 11
4. 24