Question

The fundamental note produced by a closed organ pipe is of frequency $\upsilon$ The fundamental note produced by an open organ pipe of same length will be of frequency

• A. $\frac{\upsilon}{2}$
• B. $\upsilon$
• C. 2$\upsilon$
• D. 4$\upsilon$

Answer 1

Answer: (C)

2$\upsilon$

Answer 2

Let L be length of pipe

Fundamental frequency of closed pipe is

$\upsilon_{C} = \frac{v}{4L}$ …… (i)

Where v is the speed of sound in air.

Fundamental frequency of open pipe of same length is

$\upsilon_{O} = \frac{v}{2L}$ ……. (ii)

Divide (ii) by (i), be get

$\frac{\upsilon_{O}}{\upsilon_{C}} = 2$

Or $\upsilon_{O} = 2\upsilon_{C} = 2\upsilon$