Locating Places on the Earth

Given:
- Map scale: $2.5 \text{ cm} = 500 \text{ km}$
- This means $1 \text{ cm} = \dfrac{500}{2.5} = 200 \text{ km}$

Step 1: Measure the distance on the map between the estuary of the Narmada River (near the Gulf of Khambhat) and the estuary of the Ganga River (Sundarbans/Bay of Bengal). Using the hint to round off, the measured map distance is approximately $5 \text{ cm}$.

Step 2: Convert map distance to real distance.
$$\text{Real Distance} = \text{Map Distance} \times \text{Scale factor}$$
$$= 5 \text{ cm} \times 200 \text{ km/cm}$$
$$= 1000 \text{ km}$$

Final Answer: The real distance from the estuary of the Narmada River to the estuary of the Ganga River is approximately $\mathbf{1000 \text{ km}}$.

(Note: The exact answer may vary slightly depending on the measured map distance; students should round their measurement to the nearest easy number as instructed.)

Given:
- London is located on the Prime Meridian ($0°$ longitude).
- India's Standard Time is based on $82.5°\text{E}$ longitude (IST = UTC + 5:30).

Concept: The Earth rotates $360°$ in 24 hours, which means it rotates $15°$ per hour or $1°$ every 4 minutes. Places to the east of the Prime Meridian are ahead in time.

Step 1: Calculate the time difference between India ($82.5°\text{E}$) and London ($0°$).
$$\text{Time difference} = 82.5° \times 4 \text{ minutes per degree}$$
$$= 330 \text{ minutes} = 5 \text{ hours } 30 \text{ minutes}$$

Step 2: Since India is to the east of London, India is ahead by 5 hours and 30 minutes.
$$\text{Time in India} = 12:00 \text{ pm} + 5 \text{ hours } 30 \text{ minutes} = 5:30 \text{ pm}$$

Final Answer: India is located $82.5°$ east of the Prime Meridian. Since the Earth rotates from west to east, places to the east experience noon earlier. The $82.5°$ difference translates to exactly $5$ hours and $30$ minutes, which is why when it is $12:00$ pm (noon) in London, it is $5:30$ pm in India.

We need symbols and colours in maps for the following reasons:

1. Representing real features: Maps are drawn on a very small scale. It is impossible to draw every feature (like a river, road, mountain, or building) in its actual shape and size. Symbols are used to represent these features in a simple, standardised way.

2. Saving space: Symbols allow a large amount of information to be packed into a small map area without making it cluttered or unreadable.

3. Universal understanding: Standard symbols and colours are understood by map readers all over the world, making maps universally readable regardless of language.

4. Showing different types of information: Colours help distinguish between different features at a glance — for example:
- Blue for water bodies (rivers, lakes, seas)
- Green for forests and plains
- Brown or yellow for plateaus and deserts
- White for snow-covered areas
- Red for roads or important boundaries

5. Clarity and ease of reading: Symbols and colours make maps easier to read and interpret quickly.

In summary, symbols and colours make maps accurate, informative, compact, and easy to understand.

This is an activity-based question. Students are expected to observe their surroundings and record what lies in each of the eight directions from their home or school.

The eight directions are: North (N), South (S), East (E), West (W), North-East (NE), North-West (NW), South-East (SE), and South-West (SW).

Sample Answer (for a school in a typical Indian town):

| Direction | What is found |
|-----------|---------------|
| North | A park or playground |
| South | A market or shopping area |
| East | A residential colony |
| West | A hospital or clinic |
| North-East | A temple or place of worship |
| North-West | A bus stand or road |
| South-East | A pond or water body |
| South-West | Agricultural fields or open land |

Note: Students should fill in this table based on their own observation of their actual surroundings. A compass or a map application on a phone can be used to identify directions accurately.