To increase the frequency of a stretched string from $100 \ Hz$ to $400 \ Hz$,the tension in the string has to be changed by how many times?

The fundamental frequency of a sonometer wire is $n$. If the length,tension,and diameter of the wire are all tripled,what is the new fundamental frequency?

$A$ piano string $1.5 \, m$ long is made of steel of density $7.7 \times 10^3 \, kg/m^3$ and Young's modulus $2 \times 10^{11} \, N/m^2$. It is maintained at a tension which produces an elastic strain of $1 \%$ in the string. The fundamental frequency of transverse vibrations of the string is ......... $Hz$.

When a sonometer wire vibrates in the third overtone,there are:

When a string of length $l$ is divided into three segments of length $l_1, l_2$ and $l_3$,the fundamental frequencies of the three segments are $n_1, n_2$ and $n_3$ respectively. The original fundamental frequency $n$ of the string is:

The length of a sonometer wire tuned to a frequency of $250 \ Hz$ is $0.60 \ m$. The frequency of the tuning fork with which the vibrating wire will be in tune when the length is made $0.40 \ m$ is .... $Hz$.