1. What is equator?

Horizontal lines are drawn parallel to each other in east – west direction.The line drawn midway between the North pole and the south pole is called the equator. It is the largest circle and divides the globe into two equal halves. It is also called a great circle.The rotation of the earth over its axis produces bulging at the equator.

2. What is parallels of latitude?

The parallel of latitude refer to the angular distance, in degrees, minutes and seconds of point north or south of the equator. These are the circles running round the globe parallel to the equator and maintaining uniform distance form the poles. Each parallels lies wholly in its plane which is at right angle to the axis of the earth. Lines of latitude are often referred to as parallels.

3. What is meridians of longitude?

The meridians of longitude refer to the angular distance,in degree minutes and seconds of a point east west of the Prime Meridian. The vertical lines running North–South, join the two poles.They are called the meridians of the longitude. They are spaced farthest apart at the equator and coverage at a point at each pole. Lines of longitudes are often referred to as meridians.

4. What is the shape of the earth?

The earth is nearly a sphere the rotation of the earth over its axis produces bulging at the equator. The shape of the earth present some difficulties in positioning its surface features, as there is no point of reference from which to measure the relative positions of other points. Hence a network of imaginary lines is drawn on a globe or a map to locate various places.

5. What is parallels? 

The latitude of a place on the earth’s surface is its distance north or south of the equators measured along the meridian of that place as an angle from the centre of the earth. Lines joining places with the same latitudes are called parallels. The value of equator is 0^o and the latitude of the poles are 90^o N and 90^o S. If parallels of latitude are drawn at an interval of one degree, there will be 89 parallels in the northern and the southern hemispheres each.

6. What is a great circle ?

Horizontal lines are drawn parallel to each other in east – west direction. The line drawn midway between the North pole and the South pole. Equator is the largest circle and divides the globe into two equal halves. It is also called a great circle.

7. Comparison between the parallels of latitudes and the medians of longitude ?

                                     Parallels of latitude 

      (i)    Latitude is the angular distance of a point north or south of the equator as measured in degrees.
      (ii)   All latitudes are parallel to the equator.
     (iii)   On a globe, parallels of latitudes appear as circles.
     (iv)   The 0^o latitude is referred to as the equator and the 90^o as the poles.

                                    Meridians of Longitude

      (i)    Longitude is the angular distance along the equator measured in degrees. It is measured east or west of  Greenwich (0^o), from 0^o to 180^o
      (ii)   All meridians of longitude coverage at the poles.
     (iii)   All meridians of long appear as circles running through the poles.
      (iv)  There are 360^o of longitude, 180^o each in the west and west of the Prime Meridian.

8. Difference between great circle and small circle.

The lines drawn midway between the north pole and the south pole. Equator is the largest circle and divides the globe into two equal halves.  It is called a great circle.

    All the other parallels get smaller size, in proportion to their distance from the equator towards the poles and divide the Earth into two unequal halves,also referred to as the small circle.

9. What are the importance of parallels of latitude?

The Importance of parallels of latitude are :

      (i)   Latitude is the angular distance of a point north or south of the equator as measured in degrees.
     (ii)  All latitudes are parallel to the equator. 
    (iii)  On a globe, parallels of latitudes appear as circles.
    (iv)  The distances between two latitudes is approximately 111 km.
     (v)  The 0^o latitude is referred to as the equator and the 90^o as the poles.

10. What are the importance of meridians of longitude?

The importance of meridians of longitude are :

     (i)   Longitude is the angular distance along the equator measured in degrees.
    (ii)   It is measured east or west of Greenwich ( 0^o ), from 0^o to 180^o.
   (iii)   All meridians of longitude coverage at the poles.
   (iv)   All meridians of longitude appear as circles running through the poles.
    (v)   The longitudes are used to determine the local time with reference to the time at Prime Meridian.

11. What is Prime Meridian?

The longitude of a  place is its angular distance east or west of the Prime Median. It is also measured in degrees. The longitudes vary from 0^o to 180^o eastward and westward of the Prime Meridian. The longitudes are used to determine the local time with reference to the time at Prime Meridian.

12. Determine the local time of Thimpu ( Bhutan ) located at 90^o east longitude when the time at Greenwich (0^o ) is 12.00 noon. The theme increases at a rate of A minutes per one degree of longitude, east of the prime meridian. Calculate total time difference ?

Difference between Greenwich and Thimpu
                                    = 90^o longitudes
Total time difference = 90 x 4 = 360 minutes
                                    = ³⁶⁰/₆₀ hours
       ^{6 hours}/ total time of Thimpu is 6 hours more than that at Greenwich that is 6.00 p.m.

13. Determine the local time of New Orleans ( the place, which was worst affected by Katrina Hurricane in October 2005), located at 90^o West longitude, west of the Prime Meridian. Calculate total time difference? 

Difference between Greenwich and New Orleans 
                                     = 90^o longitudes
       Total time difference  = 90 x 4 = 360 minutes
                                     = ³⁶⁰/₆₀ hours
       6 hours/ total time of New Orleans is 6 hours less than that at Greenwich that is 6.00 a.m.