Explanation:

The monsoon is a seasonal wind pattern that brings heavy rainfall to different regions of India. It is characterized by the reversal of wind direction, with the southwest monsoon bringing rain to most parts of the country, and the northeast monsoon bringing rain to the eastern coast.

Reasons for the difference in monsoon duration:

1. Distance from the sea: Kerala is located on the southwestern coast of India and is closer to the Arabian Sea. The proximity to the sea allows Kerala to receive more moisture-laden winds during the monsoon season, resulting in a longer monsoon period. On the other hand, Rajasthan is located in the northwestern part of India and is far away from the sea. Therefore, it receives less moisture and has a shorter monsoon period.

2. Late arrival and early retreat of the summer monsoon: The monsoon season in India usually starts around June and lasts until September. However, the onset of the monsoon is not the same for all regions. Kerala is one of the first regions to receive the monsoon rains, usually around the end of May or early June. This early arrival allows Kerala to have a longer monsoon period. In contrast, Rajasthan experiences a delayed onset of the monsoon, usually in July. This late arrival means that Rajasthan receives monsoon rains for a shorter duration.

3. Mountain barriers: The Western Ghats mountain range runs parallel to the western coast of India, including Kerala. These mountains act as a barrier to the monsoon winds, causing them to rise and cool, leading to heavy rainfall in the region. In contrast, Rajasthan is located on the leeward side of the Aravalli mountain range, which prevents the monsoon winds from reaching the region. As a result, Rajasthan receives less rainfall and has a shorter monsoon period.

4. Desert conditions in Rajasthan: Rajasthan is known for its arid and desert-like conditions. The Thar Desert, also known as the Great Indian Desert, covers a large part of the state. The arid climate and lack of moisture in the region limit the amount and duration of rainfall during the monsoon season.

Conclusion:

In conclusion, the difference in monsoon duration between Kerala and Rajasthan can be attributed to factors such as the distance from the sea, the late arrival and early retreat of the summer monsoon, mountain barriers, and the desert conditions in Rajasthan. These factors influence the amount of rainfall received and the duration of the monsoon season in each region.