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Assertion: A monochromatic source of lig...

Assertion: A monochromatic source of light is placed above a plane mirror as shown in figure. Fringes will be obtained at all points above O but not below it on the screen.
Reason: All reflected rays will suffer a phase difference of `pi`.

A

(a)If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

B

(b)If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.

C

(c) If Assertion is true, but the Reason is false.

D

(d) If Assertion is false, but the Reason is true.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion and the reason provided. ### Step 1: Understand the Assertion The assertion states that "A monochromatic source of light is placed above a plane mirror. Fringes will be obtained at all points above O but not below it on the screen." - **Explanation**: When light from a monochromatic source is directed towards a plane mirror, the light reflects off the mirror. The interference pattern (fringes) is formed due to the superposition of light waves from the source and their reflections. However, since the mirror blocks the light from reaching below point O, no fringes will be observed in that region. ### Step 2: Analyze the Reason The reason given is "All reflected rays will suffer a phase difference of π." - **Explanation**: When light reflects off a denser medium (like a mirror), it undergoes a phase change of π (or 180 degrees). This phase change affects the interference pattern. However, this phase change does not directly explain why fringes are not observed below point O; it only explains the nature of the interference. ### Step 3: Conclusion Now, we need to determine if both statements are true and if the reason correctly explains the assertion. - **Assertion**: True, because fringes can only be observed above point O where the light can reach the screen. - **Reason**: True, because reflected rays do indeed suffer a phase difference of π. However, the reason does not provide the correct explanation for the assertion. The reason is about the phase change due to reflection, while the assertion is about the physical obstruction caused by the mirror. ### Final Answer Both the assertion and reason are true, but the reason is not the correct explanation for the assertion. Therefore, the answer is option B. ---
To solve the question, we need to analyze both the assertion and the reason provided. ### Step 1: Understand the Assertion The assertion states that "A monochromatic source of light is placed above a plane mirror. Fringes will be obtained at all points above O but not below it on the screen." - **Explanation**: When light from a monochromatic source is directed towards a plane mirror, the light reflects off the mirror. The interference pattern (fringes) is formed due to the superposition of light waves from the source and their reflections. However, since the mirror blocks the light from reaching below point O, no fringes will be observed in that region. ### Step 2: Analyze the Reason ...
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