Question

In a Young's double slit experiment, constructive interference is produced at a certain point P. The intensities of light at P due to the individual sources are $4$ and $9$ units. The resultant intensity at point P will be

• A. $13units$
• B. $25units$
• C. $\sqrt{97}units$
• D. $5units$

Answer 1

The correct option is B

$25units$

Step 1: Given

Intensity at point 1: $I_1=4units$

Intensity at point 2: $I_2=9units$

Step 2: Determine the maximum intensity

The resultant maximum intensity in constructive interference is given by,

$$\begin{gathered} I_{max}={(\sqrt{I_1}+\sqrt{I_2})}^2 \\ ={(\sqrt{4}+\sqrt{9})}^2 \\ =25units \end{gathered}$$

Hence, option B is the correct answer.