Tag: nature and characteristics of sound waves

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Questions Related to nature and characteristics of sound waves

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

A device based on multiple reflection used for sending amplified sound in a particular direction

  1. Bulb horn

  2. Megaphone

  3. Ear trumpet

  4. All
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Megaphone is based on multiple reflection of sound. It is a horn shaped tube designed to send amplified sound in a particular direction. It is also called Loud hailer.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

Mark the incorrect statement :

 a)intensity of sound depends on the response of our ears 

b)loudness can be measured as a physical quantity 

c)loudness is a subjective quantity. 

  1. a,b

  2. a,c

  3. b,c

  4. all
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Intensity of sound is an objective quantity. It does not depend on the response of our ears. Loudness is a subjective quantity. It cannot be measured as a physical quantity.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

How does Sound produced by humans?

  1. In humans sound is produced by the voice box

  2. In humans sound is produced by the larynx

  3. In humans sound is produced by the upper part of the wind pipe.

  4. all
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In humans sound is produced by the vioce box or larynx. It is the upper part of the wind pipe. Two vocal cords are stretched across the voice box leaving a narrow slit. When the lungs force air through the slit, it vibrates and produces sound.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

The greater the surface area of the vibrating body, the________is the loudness of sound.

  1. Lesser

  2. Greater

  3. Remains same

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Loudness of the sound  $L = 10 \log _{10} \dfrac{I}{I _o}$

where $I$ is the intensity of sound.
Greater the surface area of the vibrating body, lesser will be the amplitude of the sound and thus lesser will be the intensity of the sound.

Thus lesser will be the loudness of sound.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

When we increase the loudness of sound of a TV, the property of sound that changes is:

  1. Amplitude

  2. Frequency

  3. Wavelength

  4. Speed
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Loudness of sound is proportional to the intensity and amplitude of sound. So when we turn on the volume of tv, the amplitude of sound wave increases hence, loudness of sound increases 

So the answer is A.

Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

In order to reduce the loudness of a sound we have to:

  1. decrease its frequency of vibration of the sound

  2. increase its frequency of vibration of the sound

  3. decrease its amplitude of vibration of the sound

  4. increase its amplitude of vibration of the sound
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Loudness of the sound  $L = 10 \log _{10}\dfrac{I}{I _o}$
where $I \propto A^2$   ($A$ is the amplitude of vibration of sound) 
Thus the loudness of sound varies directly as the square of the amplitude of vibration of the sound source.
Hence, the in order to reduce the loudness of sound, we have to decrease the amplitude of vibration of the sound.
Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

A 1cm long vibrates with a fundamental frequency of 256Hz. If the length is reduced to 1/4cm keeping the tension unaltered, the new fundamental frequency will be

  1. 64

  2. 256

  3. 512

  4. 1024
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
We know that $n\alpha\cfrac{1}{l}$
Thus $\cfrac{n _2}{n _1}=\cfrac{l _1}{l _1}\\n _2=\cfrac{l _1}{l _2}(n _1)=\cfrac{1\times256}{(1/4)}=256\times4=1024Hz$
Multiple choice physics sound time period, frequency and amplitude of sound amplitude, time period and frequency of a vibration nature and characteristics of sound waves

Two identical sound $A$ and $B$ each a point in the same phase. The resultant sound is $C$. The loudness of $C$ is $n$ $dB$ higher than the loudness of $A$

  1. $2$

  2. $3$

  3. $4$

  4. $6$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When two identical sound sources of the same phase are combined, the intensity doubles (I_total = 2 * I). The change in decibels is 10 * log10(I_total / I) = 10 * log10(2) = 10 * 0.3 = 3 dB. The question states the loudness is n dB higher, and 6 dB is often cited for coherent sources, but for incoherent sources, it is 3 dB. Given the options, 6 dB is likely expected if the sources are coherent.