A double-slit experiment, arrangement produces interference fringes for sodium light `(lambda = 589 nm)` that have an angular separation of `3.50 xx 0^(-3)` rad . For what wavelength would the angular separation to `10%` greater?

Options

A. 527 nm
B. 648 nm
C. 722 nm
D. 449 nm

Answer

b

Explanation

Angular separation is `lambda // d`
For angular separation to be `10%` greater, `lambda` should be `10%` greater.
`:.` New wavelength `= (589 + (589)/(10))`nm
`= (589 + 58.9)` nm
`=647.9 nm (~~ 648 "nm")`