91影视

The frequency of a string is directly proportional to the square root of its tension.

The relation between frequency and the tension is

$\mathrm{f}=\frac{1}{2\mathrm{L}}\sqrt{\frac{\mathrm{T}}{\mathrm{渭}}}$

Here, L is the length of the string, T is the tension, $\mathrm{渭}$is linear mass density.

The octave corresponds to a factor 2 in frequency. So, raise its pitch to one octave which means factor of frequency, then the tension must be of factor .

2f = 2T

= 4 T

Therefore, the tension in a guitar or violin string be increased by factor 4.

To raise its pitch two octaves which means factor 4 of frequency, then the tension must be of factor .

4f = 4T

= 16 T

Therefore, the tension increases by sixteen times as the tension before.
If the is increased then tension in the string increases large which causes strings to break so there is danger in incrementing the pitches of the string.