UPSEE 2017 Solved Paper

Given,
path difference (Δ)=13.5λ .......(i)
We know that,
path difference (Δ)=(n+

1

2

)λ ........(ii)
We can write Eq. (i) in the following form
Δ=(13+

1

2

)λ ......(iii)
From Eq (ii) and (iii), it is clear that there will be minima. So, the point will be dark.