Acoustics

Q2. Sound can propagate through a perfect vacuum.

Q3. Sound can travel through vacuum without a medium.

Q4. SONAR uses light waves.

Q5. Loudness is related to the amplitude of vibration.

Q6. Echo is associated with reflection of sound.

Q7. Increasing the amplitude of sound directly increases its pitch.

Q8. The normal human audible range is about 20 Hz to 20 kHz.

Q9. When air temperature increases, speed of sound generally decreases.

Q10. Ultrasound has a frequency below 20 Hz.