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Assertion (A) : The film which appears b...

Assertion (A) : The film which appears bright in reflected system will appear dark in the transmitted system and vice-versa.
Reason (R ) : The conditions for film to appear bright or dark in the reflected light are just reverse to those in the transmitted light

A

(A) is true and (R) is true and (R) is the correct explanation of (A).

B

(A) and (R) are true but (R) is not the correct explanation of (A)

C

(A) is true, (R) is false

D

(A) is false, (R) is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze the assertion and the reason provided. ### Step-by-Step Solution: 1. **Understanding the Assertion**: The assertion states that a film which appears bright in a reflected system will appear dark in a transmitted system. This indicates a relationship between the brightness of the film in reflection and transmission. 2. **Understanding the Reason**: The reason provided states that the conditions for a film to appear bright or dark in reflected light are just the reverse of those in transmitted light. This suggests that the criteria for interference in reflection and transmission are oppositely related. 3. **Conditions for Brightness and Darkness**: - In a reflected system, a film appears bright when the condition for constructive interference is met. This is mathematically represented as: \[ 2 \mu t \cos a = (2n - 1) \frac{\lambda}{2} \] - Conversely, a film appears dark in the reflected system when the condition for destructive interference is met: \[ 2 \mu t \cos a = n \lambda \] - In a transmitted system, the conditions are reversed. The film appears bright under destructive interference conditions and dark under constructive interference conditions. 4. **Conclusion**: Since the assertion correctly states the relationship between brightness in reflection and darkness in transmission, and the reason accurately explains why this is the case, we can conclude that both the assertion and reason are true. ### Final Answer: - **Assertion (A)** is true. - **Reason (R)** is true and provides the correct explanation for (A).
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