The third resonant length of a closed air column is 75cm . What is the first and second length

Answer 1

L= 5•λ/4,
λ =4•L/5 = 4•75/5= 60,
L1 = λ/4 =60/4=15 cm,
L2=3•λ/4=45 cm.

Answer 2

The third resonant length of a closed air column (open at one end and closed at the other end) is 75 cm. Determine the first and second resonant lengths.