MCQ
In a Young's double slit experiment the source $S$ and the two slits $A$ and $B$ are vertical with slit $A$ above slit $B$. The fringes are observed on a vertical screen $K$. The optical path length from $S$ to $B$ is increased very slightly (by introducing a transparent material of higher refractive index) and the optical path length from $S$ to $A$ is not changed, as a result the fringe system on $K$ moves
- ✓Vertically downwards slightly
- BVertically upwards slightly
- CHorizontally, slightly to the left
- DHorizontally, slightly to the right
