Question

White light passes through w double slit opening and is split into the colors of a rainbow on a screen 3m away . For m=1 which color would be farthest away from central white spot?

A.green

B.violet

C.blue

D. Yellow

E. Silver

F.all appear same locations all white spots

Answer 1

in central fringe all the seven colours will interfere constructively,since path defference is zero(zero phase difference too) and it will appear white.

for the farthest away there will be red colour because the path difference is increased the nearest colour will be violet with wavelength 350nm. and the farthest will be the red colour with wavelength 680nm.

phase difference= (2*pi*path difference)/wavelength; which implies the greater the path difference the greater the wavelength.since for the farthest away the path difference must be greater than the nearest from the central white so the farthest away there will appear red light.