Q30 / 117 · NTA Abhyas (JEE Main) 2020 · Physics · Waves and Sound

Two loudspeakers are being compared. One is perceived to be 32 times louder than the other. The difference in intensity levels between the two, when measured in decibels, is

  • A
    60
  • B
    40
  • Correct answer
    C
    50
  • D
    30

Solution

 

∆β=β2-β1=10logI2I0-10logI1I0

=10logI2I1

Increasing the intensity by a factor 10 changes the sound level by 10 dB, increasing by 100 changes β by 20 dB.

Since, 32 = 25
 ∆β=510=50 dB

Hence, the correct answer is option: 'C'.

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