Question

The fundamental frequency of closed organ pipe is equal to the frequency of first overtone of open organ pipe of length 60 cm. The length of closed organ pipe is

(1) 45 cm

(2) 30 cm

(3) 15 cm 

(4) 60 cm

Answer 1

The correct option is (3) 15 cm

\(\frac{V}{4L_1} = 2 (\frac{V}{2L_2})\)

L₁ = Length of closed organ pipe

L₂ = Length of open organ pipe 

L₂ = 4L₁ 

L₁ = \(\frac{L_2}{4}\) = 15 cm