Page 4 - K-2185 S.St (Final) 28-04-18 1C P70 LITE

(c) We know that there is a difference of 1 hour in the local time for
every 15° of longitudes. Thus, the Earth is divided into many different
time zones. There are 24 time zones on the Earth.

(d) The Earth grid is a network of latitudes and longitudes cutting across
each other. The Earth grid helps us to locate places on map or globe.

(e) The Equator, the Tropic of Cancer, the Tropic of Capricorn, the Arctic
Circle, the Antarctic Circle are some important latitudes.

6. Long answer questions :
(a) Latitudes :
(i) All latitudes are complete circles except for the North Pole and

the South Pole.
(ii) The length of the latitudes decreases as we move towards the

Poles from the Equator.
(iii) All the latitudes are located at an equal distance from each other.

Thus, they are called Parallels.
(iv) Latitudes are measured as angles north or south of the Equator.
Longitudes :
(i) All the longitudes are of the same length and they meet at the

poles.
(ii) Longitudes opposite to each other form great circles and divide

the Earth into two equal halves.
(iii) The longitudes are situated away from each other on the Equator

and this distance decreases as we move towards the poles.
(iv) Longitudes are used to measure distances in the east-west

direction.
(b) Greenwich Mean Time (GMT) : The longitude passing through

the Royal Observatory at Greenwich in England, United Kingdom
is accepted as 0° longitude and it is called the Prime Meridian. The
time at Prime Meridian is accepted as the mean time, known as the
Greenwich Mean Time (GMT).
Indian Standard Time (IST) : One such line of longitude that
passes right through the middle of India i.(e)82° 30’ E has been called
the Indian Standard Time (IST). Time on this longitude in India is
taken as the time for all over India.
(c) The International Date Line is drawn following 180° longitude to
avoid the confusion of day while travelling across 180°.
(d) The latitudes and longitudes cut across each other and form a network
called grid. This grid helps us to find the location of places on a map.
For example; Delhi is located on the globe where 28°61’N latitude
and 77°23’ E longitude intersect each other. So, the location of Delhi
is 77°23’ E 28°61’ N.
(e) The local time differ from place to place because different places have
different longitudes. All the countries have a particular local standard
time because of their unique standard meridian i.e. longitude.

Social Science (4) Class–5