4. How much is the increase in the speed of sound in the air for every 1C increase in temperature?
A. 0.06 m/s
B. 0.6 m/s
C. 6 m/s
D. 60 m/s
5. Which of the following statements is true about the speed of sound?
A. Sound travels faster in dry air than in wet air.
B. Molecules move faster so sound travels faster in warmer air.
C. Sound travels at a constant speed even if air temperature changes.
D. When comparing two media with the same phase, the sound will travel faster in a denser material.
6. Which factor does not affect the speed of sound?
A. density
B. distance
C. elasticity
D. temperature
7. Which wave property is observed when a boy shouts and hears his own voice inside the church?
A. echolocation
B. reflection
C. refraction
D. both reflection and refraction
8. Which of the following describes refraction?
A. turning back of waves
B. meeting of sound waves
C. bending of waves around edges of barriers
D. changing the speed and direction of waves ​