Question

Two optically plane glass strips of length 10 cm are placed one over the other.A thin foil of thickness 0.01 mm is introduced between them at one end to form an air film.
If the light used has wavelength 5900 A^o,find the separation between consecutive bright fringes. 

Answer 1

`tan  α  = t/l`

`=( 0.01 xx 10^(−3))/(0.1)`

`= 10^(-4)  "radian"`

`β = λ/(2μ α )`
`= (5.9 xx 10^(−7))/(2 xx 1 xx 10^(−4))`

= 2.95 x 10^-3 m 
= 2.95 mm

The separation between consecutive bright fringes is 2.95 mm