Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equ - Physics MCQ Physics | ExamTest.live

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Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m . When both the strings vibrate simultaneously, the number of beats is:

A $7$
B $8$
C $3$
D $5$

Solution & Step-by-step Explanation

The fundamental frequency of a vibrating string is f = \frac{1}{2 L} \frac{T}{μ} .Given: T = 20 N, μ = 1 g/m = 1 0^{- 3} kg/m .Speed of wave v = \frac{T}{μ} = \frac{20}{1 0 ^{- 3}} = 20000 \approx 141.42 m/s .Frequency of first string (L_{1} = 0.516 m): f_{1} = \frac{v}{2 L _{1}} = \frac{141.42}{2 \times 0.516} \approx 137.03 Hz Frequency of second string (L_{2} = 0.491 m): f_{2} = \frac{v}{2 L _{2}} = \frac{141.42}{2 \times 0.491} \approx 144.01 Hz Number of beats = ∣ f_{2} - f_{1} ∣ = 144.01 - 137.03 = 6.98 \approx 7 .

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Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m . When both the strings vibrate simultaneously, the number of beats is:

7

8

3

5

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Each of the two strings of length $51.6 cm$ and $49.1 cm$ are tensioned separately by $20 N$ force. Mass per unit length of both the strings is same and equal to $1 g/m$ . When both the strings vibrate simultaneously, the number of beats is:

Solution & Step-by-step Explanation

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Each of the two strings of length 51.6cm and 49.1cm are tensioned separately by 20N force. Mass per unit length of both the strings is same and equal to 1g/m. When both the strings vibrate simultaneously, the number of beats is:

Solution & Step-by-step Explanation

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Discussion

Each of the two strings of length $51.6 cm$ and $49.1 cm$ are tensioned separately by $20 N$ force. Mass per unit length of both the strings is same and equal to $1 g/m$ . When both the strings vibrate simultaneously, the number of beats is: