Questions, Activities and Projects

Exercises

Q1. Calculate the real distance from the estuary of the Narmada River to the estuary of the Ganga river (using scale 2.5 cm = 500 km). Solution:

1. Measure the distance on the map between the two points using a ruler (assume the measurement is approx. $7.5 \text{ cm}$ based on textbook context).
2. If $2.5 \text{ cm} = 500 \text{ km}$, then $1 \text{ cm} = 200 \text{ km}$.
3. Real Distance $= 7.5 \text{ cm} \times 200 \text{ km/cm} = 1500 \text{ km}$.

Q2. Why is it 5:30 pm in India when it is 12 pm or noon in London? Solution: London is at $0^\circ$ (GMT) and India’s Standard Time is based on $82.5^\circ \text{E}$.

• Difference in longitude $= 82.5^\circ - 0^\circ = 82.5^\circ$.
• Since $1^\circ = 4$ minutes, $82.5 \times 4 = 330$ minutes.
• $330 \text{ minutes} = 5$ hours and $30$ minutes. Since India is to the East, we add the time. So, $12:00 + 5:30 = 5:30 \text{ pm}$.

Q3. Why do we need symbols and colours in the map? Solution: Maps have limited space. We cannot draw actual buildings, trees, or railway tracks. Symbols and colours allow us to represent a vast amount of information clearly and concisely.

Q4. Find out what you have in the eight directions from your home or school. Solution: (This is a student activity. Use a compass or a phone app to identify landmarks like a park to the North, a shop to the East, etc.)

Q5. Difference between local time and standard time. Solution:

• Local Time is specific to a particular longitude based on the Sun’s position. Every longitude has a different local time.
• Standard Time is a single time adopted for an entire region or country to ensure synchronization in transport, communication, and business. For example, India has one IST despite spanning nearly $30^\circ$ of longitude.

Q6. Delhi ($29^\circ \text{N}$) and Bengaluru ($13^\circ \text{N}$) longitudes are almost the same ($77^\circ \text{E}$). How much will be the difference in local time? Solution: Since local time depends on longitude and not latitude, and both cities are on the same longitude ($77^\circ \text{E}$), there will be no difference in their local time.

Q7. True or False:

1. All parallels of latitude have the same length. — False (They get smaller towards the poles).
2. The length of a meridian of longitude is half of that of the Equator. — True (Meridians are semi-circles).
3. The South Pole has a latitude of $90^\circ \text{S}$. — True.
4. In Assam, the local time and the IST are identical. — False (IST is based on $82.5^\circ \text{E}$, while Assam is further East).
5. Lines separating time zones are identical with meridians. — False (They follow political borders).
6. The Equator is also a parallel of latitude. — True.