7 The diagram shows the fundamental mode of vibration on a s

7. The diagram shows the fundamental mode of vibration on a string. The string is vibrating with a frequency of 60 Hz Which diagram shows the second harmonic, with the correct frequency of vibration? frequency 30 Hz frequency 120 Hz frequency 20 Hz frequency 180 Hz

Solution

Fundamental mode is the first harmonic.

if wavelength in fundamenta model is lambda and frequency is f.

then in 2nd harmonic wavelength will be lambda/2 . (As figures shown in options A and C )

frequency = speed / lambda

hence frequency will be 2f.

f\' = 2 x 60 = 120 Hz

so diagram is A and C both and frequency is 120 Hz.

so no option is correct in this.