UPSC Prelims 2024 · GS Paper I

Question 14: Geography

With reference to “Coriolis force”, which of the following statements is/are correct ?

1.It increases with increase in wind velocity.
2.It is maximum at the poles and is absent at the equator.

Select the answer using the code given below :

a1 only

b2 only

cBoth 1 and 2

dNeither 1 nor 2

AnswerUPSC’s answer is (c).

Coriolis force is the deflecting force due to the earth's rotation. It is proportional to wind speed and to the sine of the latitude, so it increases with wind velocity, is maximum at the poles and is zero at the equator. It deflects winds to the right in the northern hemisphere and to the left in the southern. Both statements are correct.

1. The deflection grows with the speed of the wind.
2. The force varies with the sine of latitude: maximum at the poles, zero at the equator.

How you could have got this

If you were sure statement 1 is correct, (b) and (d) go: each of them leaves 1 out.
What you needed to know: The deflection grows with the speed of the wind.
Then, if you were sure statement 2 is correct, (a) goes: it leaves 2 out.
What you needed to know: The force varies with the sine of latitude: maximum at the poles, zero at the equator.

Only (c) is left. This one needs every statement.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong

(a) Wrong: Statement 2 is also correct.
(b) Wrong: Statement 1 is also correct.
(c) Right: the force rises with wind speed, is greatest at the poles and absent at the equator.
(d) Wrong: both statements are correct.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.