In Young's double slit experiment, if one of the slit is closed fully, what will be visible on the screen?
A diffraction pattern
If one of the slits is closed then YDSE interference fringes are not formed on the screen, so you might be tempted to say 'A slit-shaped bright spot' will be all that you can see on the screen, but no, think about what you just learnt, a fringe pattern is observed due to diffraction from the single slit that is open.