In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength `lambda =500` nm is incident on the slits. The total number of bright fringes that are observed in the angular range `-30^(@)le theta le 30^(@)` is :

Explanation

For n number of maximas
`d sin theta = n lamda`
`0.32xx10^(-3)sin30^(@)=n xx 500xx10^(-9)`
`:.n=(0.32xx10^(-3))/(500xx10^(-9))xx1/2=320`
Hence totalno.of maximas observed in angular range
`-30^(@)letheta le 30^(@)`
`=320+1+320=641`