Question

An organ pipe closed at one end has a fundamental frequency of $1500\text{Hz}$. The minimum number of overtones generated by this pipe which a normal person can hear is

• A. $4$
• B. $5$
• C. $6$
• D. $7$

Answer 1

The correct option is C $6$

In an organ pipe closed at one end, only odd harmonics are present.
Maximum audible frequency $=20000\text{Hz}$
Possible frequency for hearing are $\left(\text{in Hz}\right)$,
$1500,4500,7500,10500,13500,16500,19500$
Here, $4500\text{Hz}$ is the first overtone, hence, the maximum heard frequency is the sixth overtone $i.e.19500\text{Hz}$.
$$\begin{array}{c}\text{Why this question?}\\ \text{Tips: Only odd harmonic frequencies are produced by}\\ \text{an organ pipe closed at one end.}\end{array}$$