NCERT Solutions :
1) Multiple Choice Questions
(i) In which of the following states is the Wular lake located?
(a) Rajasthan (c) Punjab
(b) Uttar Pradesh (d) Jammu and Kashmir
Answer:
Wular Lake, renowned for its size and encircling beauty, is situated in Jammu and Kashmir.
(ii) The river Narmada has its source at
(a) Satpura (c) Amarkantak
(b) Brahmagiri (d) Slopes of the Western Ghats
Answer:
The Narmada River, known for its historic and religious significance, begins its journey at Amarkantak.
(iii) Which one of the following lakes is a salt water lake?
(a) Sambhar (c) Wular
(b) Dal (d) Gobind Sagar
Answer:
Sambhar Lake, famous for its salt production, is a notable saltwater lake.
(iv) Which one of the following is the longest river of the Peninsular India?
(a) Narmada (c) Godavari
(b) Krishna (d) Mahanadi
Answer:
The Godavari River, also known as the Dakshin Ganga, is the longest river in Peninsular India.
(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi (c) Krishna
(b) Tungabhadra (d) Tapi
Answer:
The Tapi River, with its unique geological path, flows through a rift valley.
2) Brief Answer Questions
(i) Define a water divide and give an example.
Answer:
A water divide is a geographical feature like a mountain or an upland that separates two distinct drainage basins. The Ambala region acts as a water divide between the Indus and Ganga river systems, exemplifying this phenomenon.
(ii) What is the largest river basin in India?
Answer:
The Ganga River Basin, extending over several states, is the largest in India, both in terms of size and the volume of water it carries.
(iii) Origin points of the Indus and Ganga rivers
Answer:
The Indus River originates near the Manasarovar Lake in Tibet, while the Ganga River begins at the Gangotri Glacier in the Indian state of Uttarakhand.
(iv) Name and confluence point of the Ganga’s headstreams
Answer:
The Ganga River is formed by the confluence of the Alaknanda and Bhagirathi rivers at Devprayag, creating a significant spiritual and geographical landmark.
(v) Why is the Brahmaputra less silty in Tibet compared to India?
Answer:
In the arid Tibetan landscape, the Brahmaputra River carries less silt due to lower water volume, whereas in the Indian terrain, it gathers more silt due to higher rainfall and voluminous flow.
(vi) Name two Peninsular rivers that flow through troughs
Answer:
The Narmada and Tapi rivers, unique to the Peninsular region, flow through distinct geological troughs.
(vii) Discuss the economic benefits of rivers and lakes
Answer:
Rivers and lakes are crucial for irrigation, navigation, and hydropower generation. They play a vital role in agriculture, support settlements and cities, and contribute significantly to the ecological balance and tourism industries.
3) Below are given names of a few lakes of India. Group them under two categories
– natural and created by human beings.
(a) Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (j) Rana Pratap Sagar (k) Nizam Sagar (l) Pulicat (m) Nagarjuna Sagar (n) Hirakund
Answer:
Natural Lakes:
Wular
Dal
Nainital
Bhimtal
Loktak
Chilika
Pulicat
Sambhar
Barapani
Human-made Lakes:
Gobind Sagar
Rana Pratap Sagar
Nizam Sagar
Nagarjuna Sagar
Hirakud
4) Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer:
Himalayan Rivers:
Perennial in nature, with water all year round.
Sourced from rainfall and melting snow.
Long courses, significant erosional activity, and well-developed deltas.
Peninsular Rivers:
Mostly seasonal, reliant on rainfall.
Shorter, shallower courses, with a tendency to dry up in non-monsoon months.
5) Compare the east flowing and the west flowing rivers of the Peninsular plateau.
Answer:
West-flowing Rivers:
Few in number, e.g., Narmada and Tapi.
Discharge into the Arabian Sea, forming estuaries.
Lesser sedimentation and fewer tributaries.
East-flowing Rivers:
Numerous, including Godavari, Krishna, and Mahanadi.
Flow towards the Bay of Bengal, forming extensive deltas.
Higher sediment transport and numerous tributaries.
6) Why are rivers important for the country’s economy?
Answer: Rivers are pivotal in shaping a nation’s economy. They provide essential resources for agriculture, industry, and domestic use. Riverbanks have historically been cradles of civilization, leading to the growth of cities. In India, where agriculture is a primary occupation, rivers are indispensable for irrigation, transportation, and energy generation. Additionally, rivers play a key role in maintaining ecological balance and supporting biodiversity.