Solution:
Plains are homogeneous surfaces with an imperceptible slope. They have very little variation in terms of slope.
The northern plains are located in the Northern part of India.
Its length from East to West is about 2,400 km.
The width varies from 240 to 320 km. The width also increases from east to west. The area it covers is over 7 lakh sq.km
They are formed due the sediments deposited by the Himalayan and Vindhyan rivers.