NCERT Solutions for Class 11 Geography Practical Work in Geography I Chapter 3: Latitude, Longitude and Time

Chapter at a glance

Exercise Questions

Question 1 (i)

Which are the two natural points of references on the earth?

Answer

The North Pole and the South Pole — the two points where the earth’s axis of rotation meets the surface. They are fixed reference points used to draw the grid of latitudes and longitudes.

The North Pole and the South Pole.

Question 1 (ii)

What is a great circle?

Answer

A great circle is any circle on the earth’s surface whose plane passes through the centre of the earth, dividing the earth into two equal halves. The equator is a great circle, and every pair of opposite meridians forms a great circle. The shortest route between two points on the globe lies along a great circle.

A circle whose plane passes through the earth’s centre, dividing it into two equal halves, e.g. the equator.

Question 1 (iii)

What are coordinates?

Answer

Coordinates are the latitude and longitude values that together define the exact location of a place on the earth’s surface, e.g. New Delhi: 28°36′N, 77°12′E. They are taken from the grid of parallels and meridians.

The latitude and longitude values that locate a place exactly on the earth.

Question 1 (iv)

Why does the sun appear to be moving from east to west?

Answer

Because the earth rotates on its axis from west to east. As we rotate eastward with the earth, the sun appears to rise in the east, move across the sky and set in the west. The motion of the sun is only apparent.

Because the earth rotates from west to east, making the sun appear to move from east to west.

Question 1 (v)

What is meant by local time?

Answer

Local time is the time of a place determined by the position of the sun with respect to its meridian: when the sun is highest in the sky (crosses the meridian), it is 12 noon local time. Places on the same meridian have the same local time; places east of it are ahead and those west are behind (4 minutes for each degree).

The time at a place based on the sun’s position over its meridian, with local noon when the sun is highest.

Answer

Latitudes measure distance north/south of the equator (0°–90°) as east-west circles that shrink poleward and indicate heat zones; longitudes measure distance east/west of Greenwich (0°–180°) as equal north-south semi-circles meeting at the poles and determine time.

Activity solution

Activity 2: Time in cities when it is 10 a.m. at the Prime Meridian

Earth rotates 15° per hour, so places east of Greenwich are ahead. Using each country’s standard time:

(Times ignore daylight-saving adjustments.)

Topic checklist

• Parallels of latitude and meridians of longitude
• Great circles and coordinates
• Longitude and time; local and standard time
• International Date Line

Total questions answered: 6 of 6