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Multiple choice intensity and loudness waves physics

By reducing the amplitude of a sound wave, its :

  1. Pitch increases

  2. Loudness decreases

  3. Loudness increases

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

The loudness of sound is directly proportional to amplitude of sound wave. 


loudness $\propto$ amplitude

Hence on reducing amplitude the loudness also decreases. 

Multiple choice intensity and loudness waves physics

Unit for measuring the loudness of sound is _________________.

  1. Decibel

  2. Pascal

  3. Newton

  4. Newton-metre
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Unit for measuring the loudness of sound is decibel.
The intensity or loudness of a sound depends upon the extent to which the sounding body vibrates, i.e., the amplitude of vibration. A sound is louder as the amplitude of vibration is greater, and the intensity decreases as the distance from the source increases. Loudness is measured in units called decibels. 

Multiple choice intensity and loudness waves physics

Sound levels are measured in

  1. Decimeters

  2. Decibels

  3. Deciliters

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

Answer is B.

The intensity or loudness of a sound depends upon the extent to which the sounding body vibrates, i.e., the amplitude of vibration. A sound is louder as the amplitude of vibration is greater, and the intensity decreases as the distance from the source increases.
Sound levels is measured in units called decibels. 

Multiple choice intensity and loudness waves physics

If the amplitude of the sound is made 3 times its initial value, then its loudness will become _______________ times its initial value.

  1. 9

  2. 4

  3. 16

  4. 25
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If the amplitude of the sound is made 3 times its initial value, then its loudness will become nine times its initial value.
Loudness depends on the square of the amplitude of the wave. 
That is, $Loudness\propto { (Amplitude) }^{ 2 }$.
Thus, when amplitude of the wave is tripled, the loudness increases nine times.

Multiple choice intensity and loudness waves physics

Decibel is the unit of physical quantity used for : 

  1. The speed of light

  2. The intensity of heat

  3. The intensity of sound

  4. The frequency of radiowaves
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer is C.

The intensity or loudness of a sound depends upon the extent to which the sounding body vibrates, i.e., the amplitude of vibration. A sound is louder as the amplitude of vibration is greater, and the intensity decreases as the distance from the source increases. Loudness or intensity of sound is measured in units called decibels. 

Multiple choice intensity and loudness waves physics

The loudness of sound is measured in _______ .

  1. decibels

  2. metres

  3. kilograms

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

The loudness of sound is measured in units called decibels (dB). A decibel unit expresses the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 100 dB, which is near the level most people find uncomfortably loud.

Multiple choice intensity and loudness waves physics

S. I. unit of intensity of sound is:

  1. joule s$^{-1}$ m$^{-2}$
  2. watt m$^{-2}$
  3. joule s/m$^2$

  4. both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In S. I. unit of intensity of sound is
joule s$^{-1}$ m$^{-2}$ or watt m$^{-2}$
Intensity = sound energy/time $\times$ area

Multiple choice intensity and loudness waves physics

Identify the scale which can be used to measure the intensity of sound?

  1. decibel

  2. acoustic

  3. ultrasound

  4. infrasound

  5. Hertz
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Intensity (or loudness) of sound         $L =10 \log _{10} \dfrac{I}{I _o}$

It is measured in decibel  (dB)

Multiple choice intensity and loudness waves physics

A normal human being can hear sound having an intensity level of maximum ...................

  1. 50 dB

  2. 80 dB

  3. 100 dB

  4. 150 dB
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Decibel levels help us to understand the loudness of a sound with respect to a reference level. A decibel level of zero dB represents the lowest level of sound and a level of 80 dB represents the level of pain for humans.

Multiple choice intensity and loudness waves physics

How many order of magnitude more powerful is 90 dB sound than 40 dB sound?

  1. 5

  2. 50

  3. 500
  4. $ {10}^ {5} $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$90 = 10 log (\dfrac{I _{1}}{I})$

$40 = 10 log (\dfrac{I _{2}}{I})$

$90 - 40 = 10 log (\dfrac{I _{1}}{I _{2}})$

$\dfrac{I _{1}}{I _{2}} = 10^{5}$