Question

A standing wave having $3$ nodes and $2$ antinodes is formed between two atoms having a distance $1.21\mathring{A}$ between them. The wavelength of the standing wave is

• A. $6.05\mathring{A}$
• B. $2.42\mathring{A}$
• C. $1.21\mathring{A}$
• D. $3.63\mathring{A}$

Answer 1

Answer: (C)

Distance between a node and adjoining antinod
$=\lambda /4$

From figure, distance between two atoms
$=4\times \frac{\lambda }{4}=1.21\mathring{A}$
or, $\lambda =1.21\mathring{A}$.