Two string A and b of lengths, $L_a=80\;cm$ and $L_B=x\;cm$ respectively are used separately in a sonometer. The ratio of their densities $(d_A/d_B)$ is $0.81$ The diameter of B is one -half that of A. If the string have the same tension and fundamental frequency the value of x is : - Clay6.com, a Free resource for your JEE, AIPMT and Board Exam preparation

Two string A and b of lengths, $L_a=80\;cm$ and $L_B=x\;cm$ respectively are used separately in a sonometer. The ratio of their densities $(d_A/d_B)$ is $0.81$ The diameter of B is one -half that of A. If the string have the same tension and fundamental frequency the value of x is :