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. $1.21\mathring{A}$
• B. $1.42\mathring{A}$
• C. $6.05\mathring{A}$
• D. $3.63\mathring{A}$

Answer 1

The correct option is A $1.21\mathring{A}$

The given standing wave has $2$ segments
The given standing wave is shown in the figure
As length of one loop or segment is $\frac{\lambda }{2}$, so length of $2$ segments is $2\left(\frac{\lambda }{2}\right)$
$\therefore$ $2\frac{\lambda }{2}=1.21\mathring{A}$
$\Rightarrow$ $\lambda =1.21\mathring{A}$