(10u - 0.5u)/f = λ..................
wavelength of wave reflected!!!!!!!!!!!!!!!!
let freq. there be f/ = f (10u - u) / (10u - u/2) =f .......................
(10u +u)(9.5)/f(9) = λ/ ...........................
λ/( λ/) = 9.5(9)/11(9.5) = 9/11..................................
beatiful question............y was it untouched for soooo long!!!!!!!