Question

The equation of a standing wave produced on a string fixed at both the ends is $y=0.4\sin \left(0.314x\right)\cos \left(600\pi t\right)$. The smallest length of the string would be _____________ (where $x$ is in $cm$ and $t$ is in seconds).

• A. $20cm$
• B. $40cm$
• C. $10cm$
• D. None of these

Answer 1

The correct option is C $10cm$

$\lambda =\frac{2\pi }{k}=\frac{2\pi }{0.314}=20cm$
Smallest length $d=\frac{\lambda }{2}=10cm$