only for correct answer NEED CORRECT ANSWER ASAPPP for each question

1. What would you call this?
a refraction
b. reflection
c reverberation
d. vibration

2. What type of stuff can be refracted? Choose the best answer.
a. Light
b. Sound
C. Heat
d. Anything that travels in waves

3. Light refracts when:
a. It changes speed
b. It changes from a particle to a wave
C. Its density changes
d. It encounters a solid object

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.