In Young's double-slit experiment, the two slits are illuminated by two different but identical sodium lamps. Which of the following statement about the condition of the screen is correct:
1
Screen will be dark as light from two lamps will cancell each other
2
Screen will be dark as sodium light from lamps will not be able to pass through the narrow slits.
3
There will be dark and bright fringes on the screen due to interference
4
There will be uniform illumination on screen as two sodium lamps are not coherent sources