Question

Standing waves are setup in a string of length 240 cm clamped horizontally at both ends. The separation between any two consecutive points were displacement amplitude is $3\sqrt{2}$ cm is 20 cm. The standing waves were setup by two travelling waves of equal amplitude of 3 cm. The overtone in which the string is vibrating will be :

• A. 2nd
• B. 3rd
• C. 4th
• D. 5th

Answer 1

Answer: (A)

2nd

$x_E-x_A=\lambda =20cm.\times 4=80cm$

$x=\frac{240}{80/2}=\frac{240\times 2}{80}=\frac{6}{2}$, $6^{th}$ harmonic

$5^{th}overtone.$