Explain question no 8 Ans (1) If A is the amplitude of the wave coming from a line - Physics - Wave Optics

Question

Explain question no 8 Ans (1)

I f   A   i s   t h e   a m p l i t u d e
  o f   t h e   w a v e   c o m i n g   f
r o m   a   l i n e   s o u r c e   a t  
d i s tan c e   r ,   t h e n ( 1 )   A ∝ r -
1 2 ( 2 )   A ∝ r ( 3 )   A ∝ r 1 2 ( 4 )
  A ∝ r - 2

Sakshi Gupta · Accepted Answer

Dear student,

Here the correct answer is not in any of the options so please
check it
We know from the inverse square law that the intensity of the wave
is inversely proportional to the square of the distance r
I ∝ 1/r2
Also if A is the amplitude then,
I ∝ A2
A2 ∝ 1/r2
A ∝ 1/r
A ∝ r-1

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information will clear your doubts about topic

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Explain question no.8. Ans (1) I f A i s t h e a m p l i t u d e o f t h e w a v e c o m i n g f r o m a l i n e s o u r c e a t d i s tan c e r , t h e n ( 1 ) A ∝ r - 1 2 ( 2 ) A ∝ r ( 3 ) A ∝ r 1 2 ( 4 ) A ∝ r - 2

Explain question no.8. Ans (1)

$I f A i s t h e a m p l i t u d e o f t h e w a v e c o m i n g f r o m a l i n e s o u r c e a t d i s \tan c e r, t h e n (1) A \propto r^{\frac{- 1}{2}} (2) A \propto r (3) A \propto r^{\frac{1}{2}} (4) A \propto r^{- 2}$