RAS question
The 'Coriolis Effect' influences the direction of monsoon winds in India. In the Northern Hemisphere, it deflects winds to the:
Correct answer: (B) Right of the direction of motion.
In the Northern Hemisphere, the Coriolis effect deflects winds to the right of their direction of motion.
Explanation
The Coriolis effect is the apparent deflection produced by Earth’s rotation. NCERT describes it as the force caused by Earth’s rotation that affects wind movement and says it deflects wind to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. That is why the option “right of the direction of motion” is correct for India’s monsoon winds, which operate in the Northern Hemisphere. The same rule also helps explain the anticlockwise circulation of cyclones in the Northern Hemisphere. NCERT adds two important limits: the deflection increases with wind velocity and latitude, and the Coriolis force is absent at the equator.
Why the other options are wrong
- (A) Leftward deflection is the Southern Hemisphere rule, whereas the question asks about the Northern Hemisphere.
- (C) The Coriolis force changes the horizontal direction of wind movement; it is not an upward vertical lifting force.
- (D) NCERT says the Coriolis force is absent at the equator, but it exists away from the equator and is stronger at higher latitudes.
Concept
This tests the physical-geography concept of forces controlling wind direction, especially the Coriolis force. It recurs in RAS because monsoon winds, pressure systems and cyclone circulation all depend on the same directional rule.