MCQ Sound | Chapter 12 | NCERT Class 9 Science

#1. What is the range of frequencies associated with infrasound

a) <20 Hz

b) <30 Hz

c) <40 Hz

d) <10 Hz

#2. In SONAR, we use

a) radio waves

b) ultrasonic waves

c) audible sound waves

d) infrasonic waves

#3. When we change feeble sound to loud sound, we increase its

a) wavelength

b) velocity

c) frequency

d) amplitude

#4. A key of a mechanical piano struck gently & then struck again but much harder this time. In second case

a) sound will be louder but pitch will not be different

b) sound will be louder & pitch will also be higher

c) sound will be louder but pitch will lower

d) both loudness & pitch will remain unaffected

#5. Sound travels in air if

a) there is no moisture in the atmosphere

b) particles of medium travel from one place to another

c) disturbance moves

d) both disturbance & particles of medium travel from one place to another

#6. The physical quantity that will remain unchanged after reflection of sound wave

a) velocity

b) wavelength

c) frequency

d) all of these

#7. Infrasound can be heard by

a) bat

b) rhinoceros

c) dog

d) human beings

#8. What is the range of frequency associated with ultrasound

a) > 16 KHz

b) > 18 KHz

c) > 20 KHz

d) > 22 KHz

#9. Earthquake produces which kind of sound before the main shock wave begins

a) ultrasound

b) infrasound

c) audible sound

d) none of the above

#10. In the diagram, half wavelength is

a) AB

b) BD

c) DE

d) AE

#11. Note is a sound

a) of mixture of two frequencies only

b) of a single frequency

c) of mixture of several frequencies

d) always unpleasant to listen

#12. The distance between two consecutive compression or rarefaction in wave is

a) λ

b) λ/2

c) λ/4

d) 2λ

#13. What is the audible range of human

a) 16 Hz to 16000 Hz

b) 18 Hz to 18000 Hz

c) 20 Hz to 20000 Hz

d) 22 Hz to 22000 Hz

#14. Note is a sound

a) of mixture of several frequencies

b) of mixture of two frequencies

c) of a single frequency