Which one of the following statements about the Coriolis force is not correct ?
- A.It is maximum at the Poles.
- B.It is absent at the Equator.
- C.It deflects the wind to the right direction in the southern hemisphere.
- D.It deflects the wind to the right direction in the northern hemisphere.
Correct answer
Explanation
The correct answer is C, It deflects the wind to the right direction in the southern hemisphere. In the southern hemisphere the Coriolis force turns winds to the left, not the right.
The Coriolis force is an apparent force caused by the Earth's rotation. A moving air mass keeps its own path while the ground beneath it turns, so the wind seems to bend. Ferrel's law sums it up: winds turn to the right in the northern hemisphere and to the left in the southern hemisphere. The force is directly proportional to the sine of the latitude, so it is zero at the Equator and greatest at the Poles. Its absence near the Equator is why tropical cyclones rarely form within about 5 degrees of it.
A is wrong to choose because the force really is greatest at the Poles. B is wrong to choose because it really is zero at the Equator. D is wrong to choose because winds really are deflected to the right in the northern hemisphere.
Exam tip: Ferrel's law: right in the north, left in the south; Coriolis zero at the Equator, maximum at the Poles.
Practice Questions
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