JEE PYQ: Waves And Sound Question 9
Question 9 - 2020 (02 Sep Shift 1)
Two identical strings $X$ and $Z$ made of same material have tension $T_x$ and $T_z$ in them. If their fundamental frequencies are 450 Hz and 300 Hz, respectively, then the ratio $T_x/T_z$ is:
(1) 2.25
(2) 0.44
(3) 1.25
(4) 1.5
Show Answer
Answer: (1)
Solution
Using $f = \frac{1}{2l}\sqrt{\frac{T}{\mu}}$
where, $T$ = tension and $\mu = \frac{\text{mass}}{\text{length}}$
$f_x = \frac{1}{2l}\sqrt{\frac{T_x}{\mu}}$ and $f_z = \frac{1}{2l}\sqrt{\frac{T_z}{\mu}}$
$\frac{f_x}{f_z} = \frac{450}{300} = \sqrt{\frac{T_x}{T_z}}$
$\therefore \frac{T_x}{T_z} = \frac{9}{4} = 2.25$
BETA
