Question

A wire of density 9 x 10³ kg/m³ is stretched between two clamps 1 m apart and is stretched to an extension of 4.9 x 10^-4 metre. Young's modulus of material is 9 x 10¹⁰ N/m² . Then  

(A) The lowest frequency of standing wave is 35 Hz 

(B) The frequency of 1st overtone is 70 Hz 

(C) The frequency of 1st overtone is 105 Hz 

(D) The stress in the wire is 4.41 × 10⁷ N/m²

Answer 1

Correct option: (A, B)

Explanation:

Speed of wave in wire 

Maximum time period means minimum frequency ; that means fundamental mode. 

∴ (f = 35 Hz) 

and; frequency of first overtone = v / l = 70 Hz.