Sound – MCQs Online Practice Test with Automatic scoring
CBSE Class 8 Science – Chapter Wise Study Materials Based on NCERT
Chapter 13: Sound – 30 MCQ Timed Quiz (30 Minutes)
Suitable for:
Annual Examination • Periodic Tests • Class Tests • Pre-Board / School Level Board Exam Pattern
These MCQs are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 8 board exams standard.
This is a 30-question, 30-minute timed quiz based on NCERT Class 8 Science – Chapter 13: Sound.
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MCQ Quiz – Chapter 13: Sound
A. Basics of Sound and Vibrations
Q1. Sound is a form of:
Correct Answer: B. Energy
Sound is a form of energy that produces the sensation of hearing in our ears. Vibrating objects transfer energy to the medium as sound waves.
Sound is a form of energy that produces the sensation of hearing in our ears. Vibrating objects transfer energy to the medium as sound waves.
Q2. Sound is produced when an object:
Correct Answer: C. Vibrates
Any object that vibrates (moves to and fro about its mean position) produces sound. Without vibrations, no sound is produced.
Any object that vibrates (moves to and fro about its mean position) produces sound. Without vibrations, no sound is produced.
Q3. The to-and-fro motion of a body about a fixed position is called:
Correct Answer: C. Vibration
Back-and-forth motion about a position is called a vibration or oscillation. Vibrations of objects are the basic cause of sound.
Back-and-forth motion about a position is called a vibration or oscillation. Vibrations of objects are the basic cause of sound.
Q4. Human sound (voice) is produced mainly due to vibration of:
Correct Answer: B. Vocal cords
In humans, air from the lungs makes the vocal cords in the voice box (larynx) vibrate, producing sound which is shaped into speech by the tongue, lips and teeth.
In humans, air from the lungs makes the vocal cords in the voice box (larynx) vibrate, producing sound which is shaped into speech by the tongue, lips and teeth.
Q5. The voice box is also known as the:
Correct Answer: C. Larynx
The larynx contains the vocal cords and is commonly called the voice box because it produces our voice.
The larynx contains the vocal cords and is commonly called the voice box because it produces our voice.
Q6. Children usually have:
Correct Answer: B. Shorter and thinner vocal cords
Children have shorter, thinner vocal cords, so they vibrate faster and produce higher frequency, giving a shriller (higher pitch) voice than adults.
Children have shorter, thinner vocal cords, so they vibrate faster and produce higher frequency, giving a shriller (higher pitch) voice than adults.
B. Propagation of Sound and Need for a Medium
Q7. Sound cannot travel through:
Correct Answer: C. Vacuum
Sound needs a material medium (particles) to transfer vibrations. In a vacuum there are no particles, so sound cannot travel through it.
Sound needs a material medium (particles) to transfer vibrations. In a vacuum there are no particles, so sound cannot travel through it.
Q8. Sound travels fastest in:
Correct Answer: C. Steel
Sound travels fastest in solids like steel because their particles are very close and pass on vibrations quickly. It is slower in liquids and slowest in gases.
Sound travels fastest in solids like steel because their particles are very close and pass on vibrations quickly. It is slower in liquids and slowest in gases.
Q9. The usual medium for sound to reach us on Earth is:
Correct Answer: A. Air
Most everyday sounds reach our ears through the air, which is the common medium for sound propagation on Earth.
Most everyday sounds reach our ears through the air, which is the common medium for sound propagation on Earth.
Q10. We cannot hear sound on the Moon because:
Correct Answer: C. There is almost no atmosphere
The Moon has no significant atmosphere, so there is no medium like air to carry sound waves, and hence astronauts cannot hear each other without radios.
The Moon has no significant atmosphere, so there is no medium like air to carry sound waves, and hence astronauts cannot hear each other without radios.
C. Characteristics of Sound – Amplitude, Frequency, Loudness & Pitch
Q11. Amplitude of a vibration is defined as:
Correct Answer: B. Maximum displacement from mean position
Amplitude is the maximum distance of a vibrating particle from its mean position. Larger amplitude means more energy and louder sound.
Amplitude is the maximum distance of a vibrating particle from its mean position. Larger amplitude means more energy and louder sound.
Q12. Loudness of sound mainly depends on its:
Correct Answer: A. Amplitude
A sound with larger amplitude is louder and a sound with smaller amplitude is softer, if other factors remain same.
A sound with larger amplitude is louder and a sound with smaller amplitude is softer, if other factors remain same.
Q13. The unit of frequency is:
Correct Answer: C. Hertz
Frequency is measured in hertz (Hz), which means number of vibrations per second.
Frequency is measured in hertz (Hz), which means number of vibrations per second.
Q14. Time taken to complete one full vibration is called:
Correct Answer: C. Time period
The time period is the time taken to complete one oscillation. It is related to frequency f by f = 1/T.
The time period is the time taken to complete one oscillation. It is related to frequency f by f = 1/T.
Q15. A vibrating body makes 300 vibrations in 3 seconds. Its frequency is:
Correct Answer: B. 100 Hz
Frequency = number of vibrations ÷ time = 300 ÷ 3 = 100 Hz.
Frequency = number of vibrations ÷ time = 300 ÷ 3 = 100 Hz.
Q16. The correct relation between frequency (f) and time period (T) is:
Correct Answer: B. f = 1/T
Frequency and time period are inversely related: f = 1/T and T = 1/f. If one increases, the other decreases.
Frequency and time period are inversely related: f = 1/T and T = 1/f. If one increases, the other decreases.
Q17. Pitch of a sound depends on its:
Correct Answer: C. Frequency
Pitch tells us whether a sound is shrill or deep and depends on frequency. Higher frequency → higher pitch; lower frequency → lower pitch.
Pitch tells us whether a sound is shrill or deep and depends on frequency. Higher frequency → higher pitch; lower frequency → lower pitch.
D. Audible Range, Infrasonic and Ultrasonic Sounds
Q18. The approximate audible range of frequency for a normal human ear is:
Correct Answer: B. 20 Hz to 20 000 Hz
A normal human ear can hear sounds roughly from 20 Hz to 20 000 Hz. Sounds outside this range are inaudible to humans.
A normal human ear can hear sounds roughly from 20 Hz to 20 000 Hz. Sounds outside this range are inaudible to humans.
Q19. Sounds with frequency less than 20 Hz are called:
Correct Answer: C. Infrasonic
Frequencies lower than 20 Hz are called infrasonic sounds. Humans cannot hear them, but some animals can sense them.
Frequencies lower than 20 Hz are called infrasonic sounds. Humans cannot hear them, but some animals can sense them.
Q20. Sounds with frequency greater than 20 000 Hz are called:
Correct Answer: A. Ultrasonic
Frequencies above 20 000 Hz are called ultrasonic sounds. Humans cannot hear them, but bats and dolphins can.
Frequencies above 20 000 Hz are called ultrasonic sounds. Humans cannot hear them, but bats and dolphins can.
E. Music, Noise and Noise Pollution
Q21. Which of the following is an example of musical sound?
Correct Answer: C. Melody played on a flute
A flute produces a pleasant, regular and rhythmic sound, so it is musical. The others are irregular and harsh, so they are noise.
A flute produces a pleasant, regular and rhythmic sound, so it is musical. The others are irregular and harsh, so they are noise.
Q22. Noise is best described as:
Correct Answer: B. Unwanted, unpleasant sound
Noise is any sound that is unwanted, unpleasant or disturbing to our ears, such as loud traffic or construction sounds.
Noise is any sound that is unwanted, unpleasant or disturbing to our ears, such as loud traffic or construction sounds.
Q23. Noise pollution refers to:
Correct Answer: C. Excessive, unwanted sound in the environment
Noise pollution means too much unwanted sound in our surroundings, coming from many sources like vehicles, machines and loudspeakers.
Noise pollution means too much unwanted sound in our surroundings, coming from many sources like vehicles, machines and loudspeakers.
Q24. Which of the following is NOT a harmful effect of noise pollution?
Correct Answer: D. Better hearing power
Noise pollution reduces hearing power over time; it does not improve it. It can cause headache, stress, disturbed sleep and even hearing loss.
Noise pollution reduces hearing power over time; it does not improve it. It can cause headache, stress, disturbed sleep and even hearing loss.
Q25. Which action by students will help in reducing noise pollution?
Correct Answer: C. Avoiding unnecessary use of horns
Students can help by not using horns unnecessarily, keeping volumes low and avoiding loud crackers, which all reduce noise pollution.
Students can help by not using horns unnecessarily, keeping volumes low and avoiding loud crackers, which all reduce noise pollution.
F. Human Ear – Structure, Working and Care
Q26. The visible outer part of the ear is called:
Correct Answer: B. Pinna
The external flap-like part of the ear is called the pinna. It collects sound waves and directs them into the ear canal.
The external flap-like part of the ear is called the pinna. It collects sound waves and directs them into the ear canal.
Q27. The eardrum is a:
Correct Answer: B. Thin, stretched membrane
The eardrum (tympanum) is a thin membrane that vibrates when sound waves strike it, passing vibrations to the tiny bones of the middle ear.
The eardrum (tympanum) is a thin membrane that vibrates when sound waves strike it, passing vibrations to the tiny bones of the middle ear.
Q28. Which part of the ear converts vibrations into electrical signals?
Correct Answer: C. Cochlea
The cochlea in the inner ear has fluid and sensitive hair cells. These change vibrations into electrical signals sent to the brain.
The cochlea in the inner ear has fluid and sensitive hair cells. These change vibrations into electrical signals sent to the brain.
Q29. The nerve that carries sound information to the brain is the:
Correct Answer: B. Auditory nerve
The auditory nerve carries electrical signals from the cochlea to the brain, where they are interpreted as different sounds.
The auditory nerve carries electrical signals from the cochlea to the brain, where they are interpreted as different sounds.
Q30. To protect our ears, we should:
Correct Answer: C. Avoid very loud sounds and consult a doctor if pain occurs
We should avoid loud sounds, never put sharp objects in ears, and visit a doctor if we feel pain or ringing, to prevent permanent hearing damage.
We should avoid loud sounds, never put sharp objects in ears, and visit a doctor if we feel pain or ringing, to prevent permanent hearing damage.