Previous Year Question
With reference to “Coriolis force”, which of the following statements is/are correct?
It increases with increase in wind velocity.
It is maximum at the poles and is absent at the equator.
Select the answer using the codes given below.
Correct Answer: C
Detailed Solution
The Coriolis force is an apparent force acting on moving winds, ocean currents and other moving objects because of Earth’s rotation.
Its magnitude can be represented as:
Fc = 2mΩv sin 𝛷
where m is the mass of the moving object, Ω is Earth’s angular velocity, v is the velocity of the object or wind, and 𝛷 is the latitude.
Statement 1 is correct: Coriolis force is directly proportional to wind velocity. As wind velocity increases, the magnitude of Coriolis deflection also increases. It does not act on a stationary object.
Statement 2 is correct:
At the equator, latitude is 0° and sin 0° = 0; therefore, the Coriolis force is absent.
At the poles, latitude is 90° and sin 90° = 1; therefore, the Coriolis force is maximum.
Its effect progressively increases from the equator towards the poles.
Due to the Coriolis force, moving winds are deflected:
To the right of their direction of motion in the Northern Hemisphere.
To the left of their direction of motion in the Southern Hemisphere.
The force changes the direction of wind but does not itself increase or decrease its speed.