Tag: physics

Questions Related to physics

Loudness of sound primarily depends upon

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

  1. Intensity

  2. Frequency

  3. Shape of the source

  4. Overtone

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Correct Option: A
Explanation:

Loudness that we sense is related to the intensity of sound. 

The natural frequency of vibration of a system is called.

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

  1. Eigentone

  2. Eigenfunction

  3. Period

  4. Resonance

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Correct Option: A

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

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

  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

Show answer
Correct Option: C
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.

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

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

  1. 64

  2. 256

  3. 512

  4. 1024

Show answer
Correct Option: D
Explanation:
We know that $n\alpha\cfrac{1}{l}$
Thus $\cfrac{n _2}{n _1}=\cfrac{l _1}{l _1}\\n _2=\cfrac{l _1}{l _2}(n _1)=\cfrac{1\times256}{(1/4)}=256\times4=1024Hz$

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 $A$

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

  1. $2$

  2. $3$

  3. $4$

  4. $6$

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Correct Option: D

Arrange the following sounds in the increasing order of frequencies:

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

  1. roaring of a lion

  2. buzzing of a bee

  3. a baby's voice

  4. a woman's voice

  5. a man's voice

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Correct Option: A

If the intensity of sound increases by a factor of $10^5$ , the increases in the intensity level is

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

  1. $5db$

  2. $10db$

  3. $25db$

  4. $50db$

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Correct Option: A

In a class of $100$ students each shouting at $100 dB$. Find noise level of class

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

  1. $10 dB$

  2. $100 dB$

  3. $12 dB$

  4. $120 dB$

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Correct Option: B

The fundamental frequency of a closed organ pipe is same as the first overtone frequency of an open pipe. The length of open pipe is $20\ cm$. The length of closed pipe is

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

  1. $25\ cm$

  2. $12.5\ cm$

  3. $13.33\ cm$

  4. $200\ cm$

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Correct Option: C
Explanation:
Given $:- $
Fundamental Frequency for the Open orange pipe $= ν/2l'$
where$, ν =$ Frequency and l' is the length of the open orange pipe$.$
Third Harmonic of the orange pipe $= 3ν/4l$
where$, ν =$ frequency 
and $l$ is the length of the Closed orange pipe $= 20 cm.$
Now$,$ According to the Question$,$
$3ν/4l = ν/2l'$
$⇒ 3/(4 × 20) = 1/2l'$
$⇒ 3/80 = 1/2l'$
$⇒ 2l' = 80/3$
$⇒ l' = 40/3$
$⇒ l' = 13.33 cm.$
Hence,
option $(C)$ is correct answer.

Two loud speakers are being compared, and one other. The difference in intensity levels between the two when measured in decibels.

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

  1. 60

  2. 40

  3. 50

  4. 30

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Correct Option: A