Question

ooo Verizon LTE 9:58 PM 13:57 Exit Two sources (Source 1, and Source 2) each emit light of wavelength λ-660 nm as shown in figure below. The path difference (d2-d1) between the light rays reaching the point "P" from the two sources is about 3920 nm. (a) Express this path difference in terms of λ ie. how many wavelengths (λ) is the path difference? (b) Is the interference constructive or destructive at point P? d1 Source 1 d2 Source 2

Answer 1

For constructive interference , path difference , that is path difference is an integral multiple of wavelength.

For constructive interference, path difference (d_2 - d_1) = n lambda, that is path difference is an integral multiple of wavelength. For destructive interference, path difference (d_2 - d_1) = (n + 1/2) lambda where n = 0, plusminus 1, plusminus 2, Ellipsis Wavelength of light lambda = 560 nm Path difference (d_2 - d_1) = 3920 nm (d_2 - d_1)/lambda = 3920/560 = 7, that is path difference is an integral multiple of wavelength. a) (d_2 - d_1) = 7 lambda 7 wavelength is equal to path difference. b) Since path difference is an integral multiple of wavelength. The interference at point P is constructive interference.

For destructive interference , path difference $(d_2-d_1)=\left ( n+\frac{1}{2} \right )\lambda$ Where $n=0,\pm1,\pm2,\ldots$

Wavelength of light

Path difference  

, that is path difference is an integral multiple of wavelength.

a) $(d_2-d_1)=7{\lambda}$

wavelength is equal to path difference.

b)

Since path difference is an integral multiple of wavelength.

The interference at point P is constructive interference.