Assertion (A) : The flim 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 of dark in the reflected light are just revese to those in the transmitted light

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. If assertion is true but reason is false.
D. If the assertion and reason both are false

Answer

A

Explanation

For reflected system of the film, the maxima or constructive interference is`2mutcosr= ((2n-1)lambda)/(2)` while the maxima for transmitted system of film is given by equation `2mut cosr= nlambda` Where t is thickness of the film and r is angle of reflection. From these two equations we can see that condition for maxima in reflected system and transmitted systems are just opposite.