A sonometer wire of length 1.5 m is made of steel

A sonometer wire of length 1.5 m is made of steel. The tension in it produces an elastic strain of 1%. What is the fundamental frequency of steel if density and elasticity of steel are 7.7 × 103 kg/m3 and 2.2 × 1011 N/m2 respectively?

  1. 178.2 Hz
  2. 188.5 Hz
  3. 200.5 Hz
  4. 770 Hz

Answer

f = 1/(2L)*√(T)/(AD) and Y = (TL)/(A ΔL)

From above two expressions

f = 1/(2L)√(YΔL)/(LD)

The correct option is A.