Sound Speed in Media — Practice Quiz

Question 1

Sound speed in air (γ = 1.4, M = 0.029 kg/mol, T = 300 K):

Accepted Answer

~ 347 m/s

Answer

~ 100 m/s

Answer

~ 1000 m/s

Answer

~ 5000 m/s

Question 2

Helium sound speed vs air (same T):

Accepted Answer

About 3× faster

Answer

Same

Answer

About 3× slower

Answer

Same as helium can't conduct sound

Question 3

If gas temperature doubles, sound speed:

Accepted Answer

Multiplied by √2

Answer

Doubles

Answer

Halves

Answer

Unchanged

Question 4

Sound speed in pure water at 20°C is approximately:

Accepted Answer

1500 m/s

Answer

343 m/s

Answer

5000 m/s

Answer

100 m/s

Question 5

Pressure does NOT affect sound speed in an ideal gas because:

Accepted Answer

Both — they cancel out

Answer

P and ρ both scale with same factor at constant T

Answer

B and ρ both depend on P equally

Answer

Pressure is irrelevant