A sound of 7 kHz frequency is well within the normal hearing range of most people.

Question

True.

False. <<

2. Sound is a transverse compression wave.
True.

False.<<

3. The decibel level of a sound can have a negative value.

True.<<

False.

4. The Doppler effect occurs only for compression waves, such as sound.

True.

False. <<

5. If one sound source has an intensity 30 dB above another, it has a power per unit area 1000 times stronger.

True. <<

False.

6. An observer moving toward a source at a velocity v hears the same frequency as if the observer were standing still and the source were moving towards it at the same velocity.

True.<<

False.

7. The loudness of a sound as perceived by the ear depends only on its intensity.

True. <<

False.

8. When the temperature goes up, the fundamental frequency of an organ pipe will also go up.
True. <<

False.

Answer 1

8. When the temperature goes up, the fundamental frequency of an organ pipe will also go up.
Play with this:

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html

Answer 2

were the others correct?

Answer 3

When I did it, I saw that 8 was true, is that right?

Answer 4

I put in 0.5 meter length, open both ends
at 20 deg --> 344 Hz
at 40 deg --->356 Hz
so yes, true :)

I agreed with others.