In Young's experiment distance between twe slits is 0.28 mm and distance between the slit and the screen is 1.4 m. If distance between central bright fringe and third bright fringe is 0.9 cm wavelength of light used in Young's experiment is .....

Options

A. `6000Å`
B. `5000Å`
C. `4000Å`
D. `3000Å`

Answer

A

Explanation

`sin theta_(3)=(3lambda)/() :. (x_(3))/(D)=(3lambda)/(d)`
`:. lambda=(x_(3))/(3D)=(0.9xx0.028)/(3xx140)`
`=6xx10^(-5) cm=6000Å`