HSC Science (General) 12th Board ExamMaharashtra State Board
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# Two Sound Notes Have Wavelengths 83/170 M and 83/172 M in the Air. These Notes When Sounded Together Produce 8 Beats per Second. Calculate the Velocity of Sound in the Air And Frequencies of the Two Notes. - HSC Science (General) 12th Board Exam - Physics

ConceptStudy of Vibrations of Air Columns

#### Question

Two sound notes have wavelengths 83/170 m and 83/172 m in the air. These notes when sounded together produce 8 beats per second. Calculate the velocity of sound in the air and frequencies of the two notes.

#### Solution

Given: lambda_1=83/170m, lambda_2=83/172m

no .of beats=8

find: Velocity (v) , frequency(n1, n2)

v=nlambda

n_1=v/lambda_1  and n_2=v/lambda_2

But lambda_1>lambda_2

n_2>n_1

n_2-n_1=8

v(1/lambda_2-1/lambda_1)=8 or v=(172/83-170/83)=8

v=(8xx83)/2=332 m/s

n_1=332xx170/83=680 Hz and

n_2=(332xx172)/83=688 Hz

i. The velocity of sound in air is 332 m/s.
ii. The frequencies of the two notes are 680 Hz and 688 Hz.

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#### APPEARS IN

2016-2017 (March) (with solutions)
Question 4.1 | 7.00 marks
Solution Two Sound Notes Have Wavelengths 83/170 M and 83/172 M in the Air. These Notes When Sounded Together Produce 8 Beats per Second. Calculate the Velocity of Sound in the Air And Frequencies of the Two Notes. Concept: Study of Vibrations of Air Columns.
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