Question 214: Waves Optics

Question

Two light beams of intensities 4I and 9I interfere on a screen. The phase difference between these beams on the screen at point A is zero and at point B is $$\pi$$. The difference of resultant intensities, at the point A and B, will be _________ I.

Accepted Answer

$${I_A} = {\left( {\sqrt {{I_1}}  + \sqrt {{I_2}} } \right)^2} = 25I$$
$${I_B} = {\left( {\sqrt {{I_1}}  - \sqrt {{I_2}} } \right)^2} = I$$
So, $${I_A} - {I_B} = 24I$$

Waves Optics

Two light beams of intensities 4I and 9I interfere on a screen. The phase difference between these beams on the screen at point A is zero and at point B is $\pi$. The difference of resultant intensities, at the point A and B, will be _________ I.

Choose the correct answer: