A : For best contrast between maxima and minima in the interference pattern of Young.s double slit experiment, the intensity of light emerging out of the two slits should be equa.
R : The intensity of interference pattern is proportional to square of amplitude.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true and R is false
D. Both A and R are false

Answer

To solve the given problem, we need to analyze the assertion (A) and reason (R) statements provided regarding Young's double slit experiment.

### Step-by-Step Solution:

**Step 1: Analyze the Assertion (A)**
The assertion states: "For best contrast between maxima and minima in the interference pattern of Young's double slit experiment, the intensity of light emerging out of the two slits should be equal."

- In Young's double slit experiment, the interference pattern is formed due to the superposition of light waves coming from two slits.
- For the contrast between the bright (maxima) and dark (minima) fringes to be the best, the amplitudes (and hence the intensities) of the light from both slits must be equal.
- If the intensities are equal, the difference between the maximum intensity (I_max) and the minimum intensity (I_min) will be maximized, leading to a clearer contrast.

**Conclusion for Step 1:** The assertion is **True**.

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**Step 2: Analyze the Reason (R)**
The reason states: "The intensity of the interference pattern is proportional to the square of amplitude."

- The intensity (I) of a wave is given by the square of its amplitude (A), i.e., \( I \propto A^2 \).
- In the context of interference, when two waves interfere, the resultant intensity is related to the amplitudes of the individual waves. If the amplitudes are A1 and A2, the resultant intensity can be expressed in terms of these amplitudes.

**Conclusion for Step 2:** The reason is also **True**.

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**Step 3: Check if the Reason Explains the Assertion**
While both statements are true, we need to determine if the reason correctly explains the assertion.

- The assertion focuses on achieving the best contrast in the interference pattern, which requires equal intensities from both slits.
- The reason discusses the relationship between intensity and amplitude but does not directly explain why equal intensities lead to better contrast.

**Final Conclusion:** Both statements are true, but the reason does not correctly explain the assertion. Therefore, the correct answer is that both statements are true, but the reason does not explain the assertion.

### Final Answer:
- Assertion (A): True
- Reason (R): True
- Explanation: Reason does not explain Assertion.

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