Question

A stone in hung in air from a wire which is stretched over a sonometer . The bridges of the sonometer are `40 cm` apart when the wire is in unison with a tuning fork of frequency `256 Hz`. When the stone is completely immersed in water , the length between the bridges is `22 cm` for re - establishing unison . The specific gravity of the material of the stone is
A. 0.767
B. 1.38
C. 0.983
D. 9.23

Answer 1

Correct Answer - B
`T_=Kl_1^2 " and " T_2=Kl_2^2`
By definition of specific gravity
`therefore (T_1)/(T_1-T_2) = (l_1^2)/(l_1^2-l_2^2) = ((40)^2)/((40)^2-(22)^2)=1.38`