Question

You are outdoors when you hear the constant chirp of a still cricket. You start walking toward the cricket and at some point you are able to detect that the intensity of the chirp of the cricket has increased by a factor of 4. What of the following statements is true at your new position with respect to the cricket?

a. The power delivered by the sound wave you hear has doubled.
b. The speed of the sound wave emitted by the cricket has decreased by a factor of 4.
c. The distance between you and the cricket has decreased by a factor of 2

Answer 1

C

Step-by-step explanation:

intensity = Power delivered by the sound (Watt)/ Surounding Area (m²)

I = P/A

A = πr²

r = is the distance between you and the cricket.

so in other form we can get

I = P/πr²

let take I(1) as first intensitilynyou heard and I(2) as the increased intensity.

I(1) / I(2) = r(2)² / r(1)²

1/4 = r(2)²/r(1)²

1/2 = r(2) / r(1)

r(2) = ½ r(1)

or r(2) is decreaases by a factor of 2.