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Show that when a string fixed at its two ends vibrates in 1 loop, 2 loops, 3 loops and 4 loops, the frequencies are in the ratio 1:2:3:4.

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प्रश्न

Show that when a string fixed at its two ends vibrates in 1 loop, 2 loops, 3 loops and 4 loops, the frequencies are in the ratio 1:2:3:4.

संख्यात्मक
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उत्तर

Let, there is n number of loops in the string.


The length corresponding to each loop is `λ/2`.

Now, we can write

L = `(nλ)/2`

⇒ λ = `(2L)/n`  .....[For n loops]

⇒ `v/v = (2L)/n` ......[∵ v = vλ]

⇒ v = `n/(2L)`v = `n/(2L) sqrt(T/mu)`   .....[∵ Velocity of transverse waves = `sqrt(T/mu)`]

⇒ v ∝ n   ......[∵ Length and speed are constants]

So, v1 : v2 : v3: v4 = n1 : n2 : n3 : n4

= 1 : 2 : 3 : 4

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अध्याय 15: Waves - Exercises [पृष्ठ १११]

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एनसीईआरटी एक्झांप्लर Physics Exemplar [English] Class 11
अध्याय 15 Waves
Exercises | Q 15.31 | पृष्ठ १११

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