Class 7 Science MCQs – Sound Waves (Sindh Textbook)
Sound waves travel in solvents through:
Sound waves traveling through solvents are typically longitudinal waves, where the movement of the particles is parallel to the direction of the wave.
Wavelength is symbolized as:
Wavelength is commonly symbolized by the Greek letter lambda (λ).
A normal human ear can hear sounds in the frequency range:
The normal human ear can hear sounds in the frequency range of 20–20,000 Hz.
Sound travels fastest in the:
Sound travels fastest in solids like wood because the particles are closer together, allowing sound waves to propagate more quickly.
Decibel is the unit of measurement of:
Decibel is the unit used to measure the loudness of sound.
In which medium do sound waves travel the fastest?
Sound waves travel fastest in solids because the particles are closely packed, allowing for faster transmission of vibrations.
What type of waves are sound waves in solids?
In solids, sound waves are longitudinal, meaning the particle displacement is parallel to the direction of wave propagation.
What type of waves are sound waves in liquids and gases?
In liquids and gases, sound waves are longitudinal, characterized by compressions and rarefactions.
What is the formula to calculate the speed of a sound wave?
The speed of a sound wave is calculated using the formula: speed = wavelength × frequency.
The unit of frequency is:
The unit of frequency is Hertz (Hz).
What does the wavelength of a sound wave represent?
Wavelength represents the distance between two consecutive compressions or rarefactions in a sound wave.
Which of the following determines the pitch of a sound?
The pitch of a sound is determined by its frequency.
Loudness of sound depends on:
The loudness of sound depends on its amplitude.
What is the term for areas where particles are close together in a sound wave?
Areas where particles are close together in a sound wave are called compressions.
The sensation of sound perceived by the human ear is referred to as:
The sensation of sound perceived by the human ear is referred to as loudness.
What do waves transfer from one place to another?
Waves transfer energy from one place to another.
Which type of wave needs a medium to travel?
Sound waves need a medium to travel, unlike light waves, X-rays, and gamma rays, which can travel through a vacuum.
In which direction do particles move in a longitudinal wave?
In a longitudinal wave, particles move parallel to the direction of the wave.
What are the key features of a transverse wave?
The key features of a transverse wave are crests and troughs.
Which of the following is a longitudinal wave?
A sound wave is an example of a longitudinal wave.
In which medium does sound travel the fastest?
Sound travels fastest in diamond among the given options due to its rigid atomic structure.
What unit is used to measure wavelength?
Wavelength is measured in meters.
What does the Greek letter lambda (λ) represent in wave studies?
The Greek letter lambda (λ) represents wavelength in wave studies.
What is the unit of frequency?
The unit of frequency is Hertz (Hz).
What is amplitude in a wave?
Amplitude in a wave is the distance from the rest position to a crest or trough.
Which wave property is measured in decibels (dB)?
Amplitude is the wave property measured in decibels (dB).
The number of waves passing a point in one second is called:
The number of waves passing a point in one second is called frequency.
Which formula is used to calculate frequency?
Frequency is calculated using the formula: Number of waves / Time.
In which medium are sound waves transverse?
Sound waves are not typically transverse in any medium; they are longitudinal. However, if considering surface waves, they can exhibit transverse characteristics in specific contexts like air.
What determines the pitch of a sound?
The pitch of a sound is determined by the frequency of the sound waves.
Which characteristic of sound is affected by amplitude?
Amplitude affects the loudness of sound.
What is the relationship between speed, frequency, and wavelength of a sound wave?
The relationship is given by the formula: Speed = Wavelength × Frequency.
Which of the following will have a higher-pitched sound?
A whistle will have a higher-pitched sound due to its high frequency.
What is the unit of frequency?
The unit of frequency is Hertz (Hz).
Why do children generally have higher-pitched voices than adults?
Children generally have higher-pitched voices than adults because they produce higher frequency sound waves.
Which factor does not affect the loudness of sound?
Wavelength does not affect the loudness of sound.
What happens to the sound when its amplitude increases?
When the amplitude of a sound increases, it becomes louder.
What do we call the highness or lowness of a sound?
The highness or lowness of a sound is called pitch.
What property of sound increases with higher frequency?
Pitch increases with higher frequency.
What does the speed of sound depend on?
The speed of sound depends on both wavelength and frequency.
Loudness of sound is measured in:
Loudness of sound is measured in decibels (dB).
What is the audible frequency range for a human being?
The audible frequency range for a human being is 20–20,000 Hz.
Which animal can hear the widest range of frequencies?
Whales can hear the widest range of frequencies among the given options.
Which animal can hear very high-frequency sounds that humans cannot?
Bats can hear very high-frequency sounds that humans cannot.