Which order of harmonics is missing or absent in case of stationary sound waves produced in a closed pipe ?

Which order of harmonics is missing or absent in case of stationary so

1.	Which order of harmonics is missing or absent in case of stationary sound waves produced in a closed pipe ?
Answer» SOLUTION :EVEN ORDER of harmonics is MISSING or absent. (In case of closed pipe, possible harmonics are `f_(1) , 3f_(1) , 5f_(1) , 7f_(1) …` where `f _(1) = (v)/(4L))`