$\Rightarrow \lambda=2 l \ldots(i)$
Given, $l=100 cm , v=2.53 kHz =2.53 \times 10^{3} Hz$
We know that,
$v=v \lambda$
$=v \times 2 l$ [from equation $(i)]$
$=2.53 \times 10^{3} \times 2 \times 100 \times 10^{-2}$
$=5.06 \times 10^{3} m / s$
$=5.06 km / s$
