The following 20 Multiple Choice Questions (MCQ) are based on
Chapter 10: Sound Waves: Characteristics and Applications from the NCERT Class 9
Science textbook Exploration. Each question has four options - select the
best answer and click to check.
Instructions: Read each question carefully. Choose the most
appropriate option from (a), (b), (c), or (d). Click
Show Answer to reveal the correct answer with explanation.
Multiple Choice Questions
1Sound is produced by:
(a) Vibrating objects
(b) Stationary objects only
(c) Light rays
(d) Vacuum
(a) is correct
A vibrating source sets nearby particles into oscillation, producing a sound wave.
2A tuning fork produces sound because its prongs:
(a) Melt
(b) Vibrate
(c) Become charged
(d) Stop the air
(b) is correct
The vibrating prongs alternately compress and rarefy the surrounding air.
3Sound cannot travel through:
(a) Air
(b) Water
(c) Steel
(d) Vacuum
(d) is correct
Mechanical sound waves require particles of a material medium.
4Sound in air travels as a sequence of:
(a) Crests and troughs only
(b) Compressions and rarefactions
(c) Electrons and protons
(d) Light and darkness
(b) is correct
Air particles oscillate along the direction of propagation, forming high- and low-pressure regions.
5A sound wave in air is mainly:
(a) Transverse
(b) Longitudinal
(c) Electromagnetic
(d) Stationary matter
(b) is correct
Particles vibrate parallel to the direction in which the wave travels.
6Wavelength is the distance between two successive:
(a) Unrelated particles
(b) Compressions or rarefactions
(c) Sources
(d) Echoes only
(b) is correct
It is the spatial length of one complete wave cycle.
7The SI unit of frequency is:
(a) Second
(b) Metre
(c) Hertz
(d) Decibel
(c) is correct
One hertz means one oscillation per second.
8Frequency and time period are related by:
(a) f = T
(b) f = 1/T
(c) f = vT
(d) T = fv
(b) is correct
Frequency is the reciprocal of the time for one oscillation.
9A source makes 100 oscillations in 2 s. Its frequency is:
(a) 20 Hz
(b) 50 Hz
(c) 100 Hz
(d) 200 Hz
(b) is correct
Frequency = 100/2 = 50 Hz.
10Wave speed is related to frequency f and wavelength lambda by:
(a) v = f lambda
(b) v = f/lambda
(c) v = lambda/f
(d) v = f + lambda
(a) is correct
A wave advances one wavelength during each cycle.
11Amplitude is most directly associated with perceived:
(a) Pitch
(b) Loudness
(c) Speed
(d) Wavelength only
(b) is correct
Greater amplitude generally carries more energy and produces a louder sound.
12Pitch mainly depends on:
(a) Frequency
(b) Amplitude
(c) Intensity only
(d) Medium colour
(a) is correct
Higher-frequency sounds are perceived as higher in pitch.
13The approximate human audible range is:
(a) 2 Hz to 200 Hz
(b) 20 Hz to 20 kHz
(c) 200 Hz to 200 kHz
(d) Above 20 kHz only
(b) is correct
Most young humans hear roughly from 20 hertz to 20 kilohertz.
14Lightning is seen before thunder is heard because:
(a) Thunder forms later
(b) Light travels much faster than sound
(c) Sound cannot travel in air
(d) Lightning is always closer
(b) is correct
The travel time of light is negligible compared with that of sound over the same distance.
15An echo is caused by:
(a) Refraction of light
(b) Reflection of sound
(c) Absorption of all sound
(d) Production of ultrasound
(b) is correct
Reflected sound arriving after the original may be heard separately as an echo.
16Reverberation is:
(a) Persistence of sound due to repeated reflections
(b) Complete silence
(c) Only one distinct echo
(d) Change of pitch at the source
(a) is correct
Multiple reflections make sound continue after the source has stopped.
17Auditorium walls may use sound-absorbing materials mainly to:
(a) Increase unwanted reverberation
(b) Reduce excessive reflections
(c) Increase sound speed
(d) Create a vacuum
(b) is correct
Absorption improves clarity by shortening reverberation time.
18Ultrasound has frequency:
(a) Below 20 Hz
(b) Between 20 and 200 Hz
(c) Above 20 kHz
(d) Exactly 20 Hz
(c) is correct
Ultrasonic waves lie above the upper limit of typical human hearing.
19Bats navigate in darkness mainly using:
(a) Photosynthesis
(b) Echolocation
(c) Infrasonic vision
(d) Magnetism only
(b) is correct
They emit ultrasound and interpret returning echoes.
20SONAR finds underwater distance by measuring:
(a) Only water temperature
(b) The travel time of reflected sound
(c) Colour change
(d) Electric current in air
(b) is correct
Distance is calculated from sound speed and half the round-trip echo time.
What is covered in CBSE Class 9 Science Chapter 10 Sound Waves: Characteristics and Applications?
This chapter covers all key topics from Sound Waves: Characteristics and Applications as per CBSE 2026-27 syllabus.
Is this MCQ Test useful for CBSE board exams?
Yes, designed for CBSE Class 9 board exam preparation covering the complete syllabus.
Are these CBSE Class 9 Science MCQ Test updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 9 Science?
All chapters of CBSE Class 9 Science are covered at eBookPublisher with free MCQ Test for each chapter.
Can I study Sound Waves: Characteristics and Applications online for free?
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