Question

The amplitudes of radiations from a cylindrical heat source is related to the distance are

• A. $A\propto 1/d^2$
• B. $A\propto \frac{1}{d}$
• C. $A\propto d$
• D. $A\propto d^2$

Answer 1

Answer: (B)

$A\propto \frac{1}{d}$

The intensity is inversely proportional to square of distance and intensity is directly proportional to square of amplitude. So, amplitude is inversely proportional to distance.

$I\propto \frac{1}{d^2}$

$I\propto A^2$

So, $A\propto \frac{1}{d}$