Answer
The distance between two adjacent nodes is $1.57~cm$
Work Step by Step
We can find the wavelength:
$\lambda = \frac{2\pi}{k}$
$\lambda = \frac{2\pi}{2.0\times 10^2~rad/m}$
$\lambda = 0.0314~m$
$\lambda = 3.14~cm$
Note that $\frac{\lambda}{2} = \frac{3.14~cm}{2} = 1.57~cm$
The distance between two adjacent nodes is half of the wavelength, which is $1.57~cm$
