Physical Features of India Question Answers: NCERT Class 9 Social Science - Contemporary India

(i) (b) Peninsula

(ii) (b) Purvachal

(iii) (b) Kannad

(iv) (b) Mahendragiri

(i) Due to internal heat of the earth, the currents of the semi- molten rocks starts to move towards the crust and crush it apart dividing it into the larger fragments which is known as lithospheric or tectonic plates. There are seven such major plates namely, South America, North America, Pacific, Indo–Australian, Eurasian, African and Antarctic.

(ii) Gondwana land is the name which is given to the hypothetical ‘super- continent’ that is located in Southern hemisphere. It include South America, some part of Africa (south Africa including Madagascar), part of Asia (India, Arabia, Malaya), Australia and Antarctica, prior to its break- up under forces causing the continental-drift.

(iii) The ‘Bhabar’ is that narrow belt of the plain that is covered with the pebbles and lies along the foothills of the Shiwaliks from Indus river to the Teesta. This belt is laid down by numerous streams descending down the hills.

(iv) The great or the inner Himalayas or the himadri the middle Himalayas or the himachal and outer himalayas or the shivaliks.

(v) The Malwa plateau ranges between the aravali and the vindhya ranges.

(vi) Lakshdweep islands is the islands group of India which is having coral origin.

(i) The internal heat of the earth makes the molten rocks to rush towards the earth's surface and drive the crust into the large fragments called as “Tectonic Plates”. These plates are drifting over the mantle of the earth. So as a result, when the two or more plates are pushed towards each other they are known as ‘Converging Plates’. And, on the other hand, if they are moving away from each other, they are known as ‘Diverging Plates’.

(ii)

The Indian Peninsula drifted towards the north and finally collided or fused with the much larger Eurasian Plate. As a result of this collision, the sedimentary rocks that were accumulated in the geosynclines (also known as Tethys) got folded and formed the mountain systems of the West Asia and Himalaya.

The major physiographic divisions of India are the following:
a) The Himalayan Mountain Wall of the north.
b) The Northern Plains.
c) The Peninsular Plateau.
d) The Indian Dessert.
e) The Coastal Plains.
f) The Islands.
The following table compares and contrasts between the relief of the Himalayan region with that of the Peninsular plateau.

The northern plains have been formed from the alluvium where mountain rivers have been deposited. This turned the soil into fertile surfaced land for growing a rich harvest of variety of crop which led to the development of the Indus river valley civilisation. The rich soil was further assisted by favourable climate and constant water supply from these rivers. Between the mouths of the Indus and the ganga, Brahmaputra; the north Indian plain covers the distance of 3200km. It is 300 to 150 km wide at some places. The north Indian plains contains the Indus river system in the west and the ganga Brahmaputra river system in the east. Firstly it includes Jhelum, Chenab, ravi, beas, satluj. The Indus flows into the Arabian sea; the second includes ganga, it's tributaries and the Brahmaputra that combines as meghna as they drains into the bay of Bengal. They form the world's largest and fastest growing delta. The difference in relief has led the north Indian plains to be divided into four zones:
(i) Bhabhar,
(ii) Tarai,
(iii) Bangar and,
(iv) Khaddar.

(i) The Indian desert: lies towards the western margins of the aravali hills. It is an undulating sandy plain covered with sand dunes known as barchans. This region receives very low rainfall below about 150 mm per year (15 cm). It contains arid climate with low vegetation canopy. Streams appear during the rainy season. Soon after they disappear into the sand as they don't have enough water to reach the sea. Luni is the only large river in this region.

(ii) The central highlands: lies to the north of the Narmada river. It covers the major part of the malwa plateau. The rivers in this region flows from southwest to northeast that indicates the slope of this region. It is wider in the west and narrower in the east. Bundelkhand and baghelkhand points the eastward extension of this plateau. The plateau further extends from eastwards into the chhotanagpur plateau.

(iii) The island groups of India: India has 2 main island groups, Lakshadweep, Andaman and Nicobar island. The lakshadweeep consists of this group that are formed of coral deposits known as atolls in Malayalam which refer to their ring or horse shoe-shaped. The Andaman and nicobar islands on the other hand are larger in size. They are more in numbers and more widely scattered. There are about 200 islands in the Andaman group and 19 islands in the nicobar group.