Question 119: Waves Optics

Question

The two light beams having intensities I and 9I interfere to produce a fringe pattern on a screen. The phase difference between the beams is $$\pi$$/2 at point P and $$\pi$$ at point Q. Then the difference between the resultant intensities at P and Q will be :

Accepted Answer

$${I_P} = I + 9I + 2\sqrt {I 	imes 9I} \cos {\pi  \over 2} = 10I$$
$${I_Q} = I + 9I + 2\sqrt {I 	imes 9I} \cos \pi  = 4I$$
So, $${I_P} - {I_Q} = 6I$$

Answer

2 I

Answer

6 I

Answer

5 I

Answer

7 I

Waves Optics

The two light beams having intensities I and 9I interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\pi/2 at point P and \pi$ at point Q. Then the difference between the resultant intensities at P and Q will be :

Choose the correct answer: