Question

If the length of a stretched string is shortened b
20% and the tension is increased by 21% then the
frequency (Let n = initial frequency)
(1) Increases by 20.5%
(2) Increases by 37.5%
(3) Increases by 30.5%
(4) Decreases by 37.5%​

Answer 1

Frequency will be increased by 37.5 %

Explanation:

We have given that the length is shorten by 20 % and tension is increased by 21 %

Let initially the length is $l_1$

Then after shorten length will be $l_2=l_1-0.2l_1=0.8l_1$

And let initially the tension is $T_1$

So after increasing 21 % tension will be $T_2=T_1+0.21T_1=1.21T_1$

We know that frequency is given by

$n=\frac{1}{2l}\sqrt{\frac{T}{m}}$

$\frac{n_2}{n_1}=\frac{l_1}{l_2}\sqrt{\frac{T_2}{T_1}}$

$\frac{n_2}{n}=\frac{l_1}{0.8L_1}\sqrt{\frac{1.21}{T_1}}$

$n_2=01.375n_1$

So frequency is increased by 37.5 %

learn more

Relation between frequency and tension

https://brainly.in/question/8787732

Answer 2

Answer:

increased by 37.5persentage

Explanation:

hope understood