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NCERT Solutions Exploring Society: India and Beyond Chapter 1 –25End-of-chapter exercise — Questions, activities and projects

Book page 24 Updated on2026-09-05

Q1.
Returning to page 10 and to Fig. 5.2 in Chapter 5 of this textbook, taking the scale to be 2.5 cm = 500 km, calculate the real distance from the estuary of the Narmada River to the estuary of the Ganga river. (Hint: round off your measurement on the map to an easy number.)
Answer

Step 1 — find the two estuaries on the map of India. The Narmada flows westward and meets the Arabian Sea in the Gulf of Khambhat in Gujarat. The Ganga flows eastward and meets the Bay of Bengal through the delta of the Sundarbans in West Bengal.

Step 2 — measure the straight line between them with your ruler. It comes to about 8 cm (this is the “easy number” the hint asks you to round off to).

Step 3 — use the scale.

2.5 cm on the map = 500 km on the ground
So 1 cm = 500 ÷ 2.5 = 200 km
Measured distance = 8 cm
Real distance = 8 × 200 = 1,600 km

So the two river mouths are roughly 1,600 kilometres apart in a straight line — about the same as the flying distance from Ahmedabad to Kolkata.

Estuary: the place where a river meets the sea (the book's margin note on page 24). The Narmada has a funnel-shaped estuary; the Ganga instead builds a huge delta, the largest in the world, shared by India and Bangladesh.
Why your answer may differ a little: the exact points you choose on the coast, and how you round your measurement, can change the result by 100 km or so. That is normal — a scale gives a good estimate, not a surveyor's figure. What must be right is the method: measure, then multiply by what 1 cm stands for.
Q2.
Why is it 5:30 pm in India when it is 12 pm or noon in London?
Answer

Because India's clocks are set 5 hours 30 minutes ahead of Greenwich, and that number comes straight from longitude.

London (Greenwich) is on the Prime Meridian, 0°
India's standard meridian = 82°30′E (it passes near Mirzapur, Uttar Pradesh)
The Earth turns 15° in one hour
82°30′ ÷ 15° = 5.5 hours = 5 hours 30 minutes
12:00 noon GMT + 5:30 = 5:30 pm IST
0° Greenwich 82°30′E India 12:00 noon 5:30 pm 82.5° eastward = 5 h 30 min added going east, add time  •  going west, subtract time
India lies east of Greenwich, so Indian clocks are ahead — by exactly 5 hours 30 minutes.
Why ahead and not behind: the Earth spins from west to east, so places to the east meet the Sun earlier. India is east of London, so India's day starts earlier and its clock reads later.
Q3.
Why do we need symbols and colours in the map?
Answer

Symbols are needed because of space, and colours because of speed of reading.

  • There is no room to draw everything. On a map of a district you cannot draw each house, temple and well as a picture. A tiny fixed sign does the job.
  • They make maps universal. The Survey of India fixes one set of signs, so an Indian map means the same thing to every reader — a person who cannot read the labels can still see where the railway line and the river are.
  • They save time. Colours are read at a glance: blue = water, green = plains, forests and gardens, yellow/brown = plateaus and hills, white = snow and ice, black/red = roads, railway lines and settlements.
  • They allow comparison. On a thematic map, shades of one colour instantly show which State has the most rainfall or the highest literacy, without reading a single number.
Test it on yourself: open any physical map of India. Without reading one word you can see the brown Himalaya in the north, the yellow-brown Thar in the west, the green Ganga plain, and the blue seas on three sides. That is the work of colour and symbols.
Q4.
Find out what you have in the eight directions from your home or school.
Answer

How to do it properly:

  1. Stand at the gate of your home or school. Fix north first — by the morning Sun (it rises roughly in the east), by a compass, or by a phone compass.
  2. Draw a compass rose on a page: N at the top, then clockwise NE, E, SE, S, SW, W, NW.
  3. Look along each of the eight lines and write down the nearest important landmark in that direction.
  4. Check the doubtful ones with your parents or teacher, or on a printed map of your town.
DirectionSample answer — from my school
North (N)The village pond and the water tank
North-east (NE)The Primary Health Centre
East (E)The main road and the bus stop
South-east (SE)The weekly market ground
South (S)Wheat fields and a canal
South-west (SW)The Gram Panchayat office
West (W)My home and the post office
North-west (NW)The temple and a mango orchard
Write your own. Replace every entry above with what is actually around your school, then draw the eight arrows on a rough map with the landmarks marked. Keep it — you can use the same sketch for the “map of your locality” activity on page 11.
Q5.
What is the difference between local time and standard time? Discuss it in groups, with each group writing an answer in 100 to 150 words. Compare the answers.
Answer

Model answer (about 140 words):

Local time is the time shown by the Sun at a particular place. When the Sun is highest over a meridian, it is 12 noon for every place on that meridian. Since the Earth turns 15° in an hour, each meridian has its own local time; a place 15° to the east is one hour ahead. Standard time is a single clock time that a whole country agrees to keep, based on one chosen meridian passing through it. India's standard meridian is 82°30′E, near Mirzapur in Uttar Pradesh, so Indian Standard Time is 5 hours 30 minutes ahead of Greenwich Mean Time. Because of this, the Sun rises in Tinsukia in Assam nearly two hours before it rises in Porbandar in Gujarat, yet clocks in both towns show the same time. Local time follows the Sun; standard time follows an agreement that keeps trains, schools and offices working together.

For the group comparison: good answers will all contain four things — (1) local time is decided by the Sun and the meridian, (2) standard time is one time chosen for a country, (3) the figure 15° per hour or 1° = 4 minutes, and (4) one clear Indian example. Check each group's answer against this list rather than against its length.
Q6.
Delhi's and Bengaluru's latitudes are 29°N and 13°N; their longitudes are almost the same, 77°E. How much will be the difference in local time between the two cities?
Answer

There will be no difference — the local time in both cities is the same.

Local time depends only on longitude
Longitude of Delhi = 77°E, longitude of Bengaluru = 77°E
Difference in longitude = 0°
Difference in local time = 0 × 4 minutes = 0 minutes

The two cities lie almost on the same meridian, one nearly 1,750 km north of the other. The Sun crosses that meridian at the same moment for both, so it is midday in Delhi and in Bengaluru at the same instant.

Then what does the latitude change? Not the time of noon, but the length of the day and the climate. Bengaluru at 13°N gets days of nearly equal length all year and a mild climate. Delhi at 29°N has long summer days and short winter days, a very hot May and a cold January. Latitude decides climate and season; longitude decides time.
Careful: sunrise in Delhi and Bengaluru is not at the same clock time, because latitude changes how early the Sun climbs above the horizon at different seasons. But noon — the Sun at its highest — happens together, and that is what local time measures.
Q7.
Mark the following statements as true or false; explain your answers with a sentence or two. (a) All parallels of latitude have the same length. (b) The length of a meridian of longitude is half of that of the Equator. (c) The South Pole has a latitude of 90°S. (d) In Assam, the local time and the IST are identical. (e) Lines separating the time zones are identical with meridians of longitude. (f) The Equator is also a parallel of latitude.
Answer
StatementTrue / FalseReason
(a) All parallels of latitude have the same length.FalseThe Equator is the longest circle. The parallels grow smaller as you move towards either pole, until 90°N and 90°S are only points.
(b) The length of a meridian of longitude is half of that of the Equator.TrueA meridian is a half-circle from pole to pole, while the Equator is a complete circle of the same size. So a meridian is half as long.
(c) The South Pole has a latitude of 90°S.TrueLatitude is counted from 0° at the Equator to a maximum of 90° at each pole — 90°N for the North Pole and 90°S for the South Pole.
(d) In Assam, the local time and the IST are identical.FalseIST is based on 82°30′E, but Assam lies near 92°–95°E. Its local time runs roughly 40 minutes to an hour ahead of IST, which is why the Sun rises there so early.
(e) Lines separating the time zones are identical with meridians of longitude.FalseThey only follow the 15° meridians broadly. As Fig. 1.8 shows, they bend to follow international borders so that a country is not divided between two standard times.
(f) The Equator is also a parallel of latitude.TrueIt is the 0° parallel — the starting line from which all other latitudes are measured, and the largest of them all.
Watch the pair (a) and (b) together: all meridians are equal in length, but parallels are not. Students often mix the two. Remember it from the globe: the meridians all meet at the poles, so they must be equal; the parallels are stacked circles of different sizes.
Q8.
Solve the crossword below. ACROSS: 1. Lets you squeeze a huge area into your map; 4. A convenient sphere; 5. The longest parallel of latitude; 6. The place the Prime Meridian is attached to; 8. So convenient to find your way; 10. A measure of the distance from the Equator. DOWN: 2. A measure of the distance from the Prime Meridian; 3. These two together allow us to locate a place; 6. What latitudes and longitudes together create; 7. The time we all follow in India; 9. On top of the world; 11. An abbreviation for a line across which the day and date change.
Answer
No.ClueAnswer
1 AcrossLets you squeeze a huge area into your mapSCALE
4 AcrossA convenient sphereGLOBE
5 AcrossThe longest parallel of latitudeEQUATOR
6 AcrossThe place the Prime Meridian is attached toGREENWICH
8 AcrossSo convenient to find your wayMAP
10 AcrossA measure of the distance from the EquatorLATITUDE
2 DownA measure of the distance from the Prime MeridianLONGITUDE
3 DownThese two together allow us to locate a placeCOORDINATES
6 DownWhat latitudes and longitudes together createGRID
7 DownThe time we all follow in IndiaIST
9 DownOn top of the worldPOLE
11 DownAn abbreviation for a line across which the day and date changeIDL
S C A L E O N C G L O B E I O E Q U A T O R U D D I G R E E N W I C H M A P R A S O I T T L A T I T U D E E E D S L 1 2 3 4 5 6 7 8 9 10 11
The completed crossword. The red numbers are the clue numbers printed in your book.
How the crossings check your answers: the L of SCALE begins LONGITUDE; the G of GREENWICH begins GRID; the I of GREENWICH begins IST; the P of MAP begins POLE, whose L is the L of LATITUDE; and the I of LATITUDE begins IDL (International Date Line).
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