In Young's double slit experiment how many maximas can be obtained on a screen (including the central maximum) on both sides of the central fringe if  λ=2000 Å and  d=7000 Å

For maximum intensity on the screendsinθ=nλ ⇒sinθ=nλd=n(2000)7000=n3.5Since maximum value of  sinθ is 1So n=0,  1,  2,  3,  only. Thus only seven maximas can be obtained on both sides of the screen.