# Frequency, speed of sound

## Homework Statement

A 256 Hz tuning fork produces the first harmonic in a tube filled with air and having one closed and one open end. If the tube were filled with helium where the speed of sound is 965 m/sec, what frequency would be needed to produce the first harmonic? Assume the speed of air at the same temperature is 330 m/sec.

v=lambda*f

## The Attempt at a Solution

I have tried:

f=256 Hz, speed of helium=965m/s
lambda=v/f=965/256=247040m
f=v/lambda=965Hz/247040m=0.0039Hz