Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).
Assertion (A) : Voices of men and women are different.
Reason (R) : Length and thickness of vocal cord is

Question

Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).
Assertion (A) : Voices of men and women are different.
Reason (R) : Length and thickness of vocal cord is different in men and women.
Select the correct answer from the code given below :
Code :

UnlockIAS · Accepted Answer

Correct — D, both (A) and (R) are true and (R) is the correct explanation of (A). Read that option text before you do anything else, because this booklet has swapped the code you have drilled: here (d) is the 'both true and R IS the explanation' slot and (a) is the 'both true but R does NOT explain A' slot — the exact reverse of the ordinary UPSC arrangement. Now the substance. The Assertion is true and needs no defence: adult male and adult female voices differ audibly, and the difference is measurable. The pitch we hear is the fundamental frequency at which the vocal folds open and close, and it averages roughly 125 hertz in an adult man against roughly 210 hertz in an adult woman, with children above 300 hertz. The Reason is true as well. The vocal folds of an adult male are about 1.75 to 2.5 centimetres long; those of an adult female about 1.25 to 1.75 centimetres. The male folds are also thicker and more massive. And the Reason does explain the Assertion, because the vocal folds obey the same law as any other vibrating body under tension — the frequency falls as the vibrating length increases and as the mass of the vibrating element increases, and rises as the tension increases. Longer and heavier folds therefore vibrate more slowly, and a slower vibration is a lower pitch. This is the same physics that makes the thick, long bass string of a sitar sound deeper than the thin, short treble string. The anatomical difference is not merely a fact standing beside the audible difference; it is the cause of it. Both statements are true and the Reason is the correct explanation of the Assertion — and on this paper that is option (d).

Why the other options are wrong — (a) This is the trap the booklet is built around, and it catches the candidate who reasons perfectly. Work the substance out correctly — both statements true, and the Reason is the cause of the Assertion — then reach for the position that verdict occupies on an ordinary UPSC paper, and you land here. On this booklet (a) carries the opposite meaning. On the merits it is wrong too: the Reason is not an unrelated true statement sitting beside the Assertion. Delete the difference in fold length and thickness and the difference in voice disappears with it, which is precisely what an explanation means.  (b) The Reason is not false. The dimensions are measured, not inferred: adult male vocal folds run about 1.75 to 2.5 centimetres and adult female folds about 1.25 to 1.75 centimetres, and the male folds are the thicker and more massive pair. The visible sign of the same growth is the laryngeal prominence, the Adam's apple, which appears when the larynx enlarges at puberty under the action of androgens.  (c) The Assertion is not false. Male and female voices differ in a way that can be put on an instrument: the average fundamental frequency is roughly 125 hertz for adult men and roughly 210 hertz for adult women, close to an octave apart. Ranges do overlap at the margins — some men speak high and some women low — but the question says the voices are different, not that every man is lower than every woman, and as a general statement it is plainly correct.

Concept: Speech begins in the larynx, the voice box seated at the top of the windpipe. Air driven up from the lungs forces the two vocal folds apart; their own elasticity and the drop in pressure between them snap them shut again, and this cycle repeats hundreds of times a second, chopping the airstream into a buzzing tone. The rate of that cycle is the fundamental frequency, and the ear reads it as pitch. What sets the rate is the same set of variables that governs any vibrating string: frequency falls as the vibrating length grows and as the mass of the vibrating element grows, and rises as tension grows. So longer, thicker, heavier folds give a deeper voice, and the throat and mouth above them then act as a resonating chamber that shapes the buzz into vowels and consonants.

State PCS 2025 Q126 — Science & Technology PYQ with Answer

State PCS 2025 Q126 — Science & Technology PYQ with Answer