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, $\lambda=1.21\,\mathring{A}$.