A) As a wind instrument warms up, the resonant frequencies of the instrument tend to slightly decrease.

Question

B) If the air in a concert hall warms up, the resonant frequencies of the string instruments will change precisely the same as the resonant frequencies of the wind instruments.
C) If you pluck a string one third of the way along its length, you tend to suppress the third harmonic (n=3).
D) If the slide of a trombone is pushed outwards (making the effective tube length longer), all the resonant frequencies of the instrument increase.

I thought the answer was TTFF, but it was wrong. Any idea?

Answer 1

speed sound decreases when air is warmed. If speed goes up, frequency decreases A)T
B. strings slightly expand, reducing tension, so f goes down,but not at the same rate, F
C. T. The third homonic would a node at that position, you are forcing a vibration there.
D. length longer, wavelength longer, Freq decrease. F

Check my thinking.

Answer 2

Its actually FFTF, thanks for the help