Question

The two northeastern hills that block the South West Monsoon winds and cause heavy rains in Assam are________ .
a)Arakan Yoma and Pegu Yoma
b)Garo, Khasi and Jaintia hills
c)Barail and Patkai hills
d)Khasi and Pegu Yoma

Answer 1

Hint:The term monsoon is used to define seasonal reversal of winds that bring precipitation along. India receives two kinds of monsoons- South West monsoon in the summer and North East monsoon in winters.

Complete Answer:Intense low pressure over Tibetan plateau leads to moist wind from the South of Indian ocean to come towards India which ultimately leads to rainfall in most parts of India.
Assam receives rainfall under south west monsoon from the months of June to September.

Let us look at the options given to us-

Option A- Arakan Yoma and Pegu Yoma are mountain ranges in Myanmar. Arakan range blocks the south west monsoons from reaching central Myanmar and this causes extreme rainfall in the western slopes.

Option B-Garo Khasi and Jaintia hills is the correct answer as these hills are part of Shillong plateau and block the south west monsoon winds. This happens as monsoon winds are lifted over these mountain ranges which leads them to cool down, form orographic clouds and fall down as heavy rainfall. This is an example of orographic precipitation.

Option C- Barail range is the range that divides Brahmaputra and Barak basin. Patkai hills form the north eastern border between India and Myanmar. Both the hills are part of Purvanchal or Eastern Himalayn range.

Option D-Khasi and Pegu Yoma are two distinct hills. Khasi hills are low mountains found in the Shillong Plateau whereas Pegu Yoma are low mountains found between Irrawaddy and Sittaung river in central Myanmar.

Therefore the correct answer is option B.

Note:Just like Assam, the windward sides of Western Ghats receive heavy rainfall. The Ghats makes the monsoon air rise and cool down which leads to precipitation. This is why central Maharashtra remains dry when the Konkan coast receives heavy rainfall. Similarly the windward side of Assam receives more rainfall than the leeward side.