CBSE Questions for Class 8 Physics Sound Quiz 13 - MCQExams.com

The sound in the audible range is called 
  • Ultra sonic
  • Sonic
  • Sub sonic
  • Light sound
Relation between frequency and time period is 
  • Time period = frequency
  • (Frequency) =$$2 \times$$ time period
  • Frequency $$ = \dfrac{1}{{\text{Time period}}} $$
  • Frequency $$ = \dfrac{{\text{Time period}}}{2} $$
A pendulum oscillates $$20$$ times in $$2$$ seconds then its time period is 
  • $$0.01 $$ sec
  • $$ 0.001 $$ sec
  • $$ 0.02 $$ sec
  • $$ 0.1 $$ sec
In a clock, the time period of hour hand is :
  • $$1$$ hour
  • $$24$$ hour
  • $$12$$ hours
  • None of these
The time period of the second hand in a clock is :
  • $$1$$ minute
  • $$1$$ hour
  • $$2$$ hours
  • $$24$$ hours
Infrasound is the sound with frequencies :
  • above $$20$$ kHz
  • below $$20$$ Hz
  • between $$20$$ Hz to $$20$$ kHz
  • all the above
The time period of a vibrating body is $$ 0.02\,s $$. The frequency of the vibrating body will be 
  • $$ 100 \,Hz $$
  • $$ 20 \,Hz $$
  • $$ 50\,Hz $$
  • $$ 1 \,Hz $$
The siren of an ambulance needs to be a loud and piercing sound. Therefore, its main characteristics should be:
  • high pitch and large amplitude
  • low pitch and large amplitude
  • high pitch and small amplitude
  • low pitch and small amplitude
Choose whether true or false:-
The eardrum is stretched.
  • True
  • False
.......... is the number of vibrations of a body in one second.
  • Frequency
  • Pitch
  • Time-period
  • Compression
A metallic spoon falls on a metal plate making a huge sound and upon bouncing from the plate, it falls on to the pile of sand below it with no noise being heard. Sound is not heard on sand because
  • Sound is absorbed by sand particles
  • Sound generated by the plate is more than the sand particles
  • Vibration of metal plate is more than sand particles
  • Sand does not vibrate
The sound having a frequency less than 20 Hz is called .......... .
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  • Infrasonic
  • Ultrasonic
  • Energy
  • Vibrations
Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
  • The pitch of the sound.
  • The frequency of the sound.
  • The speed of the sound.
  • The wavelength of the sound.
Which of the following can caused by noise pollution?
  • Lack of sleep
  • Hypertension
  • Anxiety
  • All of the above
In space, no one can hear an explosion :
  • True
  • False
The audible range for humans is $$20\ Hz$$ to $$20,000\ Hz$$.
  • True
  • False
Any sound of frequency less than $$20\: Hz$$ is not audible to human ears.
  • True
  • False
Some whistles are designed to produce waves that can attract the attention of dogs but humans do not notice these waves. What kind of waves are these?
  • These are normal sounds waves whose frequency is less than $$20\ Hz$$. Humans cannot hear them because these waves have frequencies below the audible range.
  • These are normal sounds waves whose frequency is more than $$20,000\ Hz$$. Humans cannot hear them because these waves have frequencies above the audible range.
  • These are electromagnetic waves.
  • These are supersonic sound waves.
In sound wave:
  • Direction of vibration of particle is same as direction of energy
  • Direction of vibration of particle is perpendicular to the direction of energy
  • Vibration of particles does not exist
  • None of these
Statement 1: Loudness is the characteristic of a musical sound by which a loud sound can be distinguished from a faint sound.
Statement 2: Echo is always produced when sound is incident on the hard and polished surface.
  • Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
  • Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.
  • Statement 1 is true but statement 2 is false
  • Statement 1 is false but statement 2 is true
The waves produced by simple pendulum (having time period $$2$$ seconds) are.
  • Infrasonics
  • Audible
  • Ultrasonic
  • None of these
When sound propagates in air, it does not carry energy with it.
  • True
  • False
Infrasound can be heard by :
  • Elephant
  • bat
  • human beings
  • dog
Which of these is not a function of the ear drum?
  • Send vibrations to the inner ear
  • Comprehend the vibrations of any sound
  • Vibrate when sound enters
  • None of these
The eardrum sends the vibrations to the brain.
  • True
  • False
Sound travels directly to the eardrum.
  • True
  • False
Th eardrum sends the vibrations to the _______?
  • Brain
  • Outer ear
  • Nerve Cell
  • Middle ear
Which of these correctly represents the definition of frequency?
  • The number of oscillations per second
  • The number of oscillations per minute
  • The number of oscillations per hour
  • The number of oscillations per day
Choose whether true or false:-
We must never put a sharp object in our ear.
  • True
  • False
Frequency is expressed in?
  • Seconds (s)
  • Kelvin (K)
  • Hertz (Hz)
  • Metre (m)
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