Question

A stretched string of length $1m$ has a frequency of $256Hz.$ If length of the string is decreased by $0.36m$, then the frequency will be:

• A. $200Hz$
• B. $400Hz$
• C. $100Hz$
• D. $512Hz$

Answer 1

Answer: (B)

$400Hz$

frequency $=\frac{\nu }{2l}=256\times 2\times 1=\nu$
Now taking same $\nu$
$f=\frac{\nu }{2l}$
$=\frac{256\times 2\times 1}{2\times 0.64}$ (since length is decreased by $0.36m$ here length is $1-0.36=0.64m$)
$=400Hz$