White coherent light (400 nm—700 nm) is sent through the slits of a Young’s double slit experiment (figure 17-E3). The separation between the slits is 0.5 mm and the screen is 50 cm away from the slits. There is a hole in the screen at a point 1.0 mm away (along the width of the fringes) from the central line. (a) Which wavelength(s) will be absent in the light coming from the hole? (b) which wavelength(s) will have a strong intensity?


The distance between the screen and the slit,


separation between the slits


The path difference at a point y above the center on the screen is


—————(1)


And the condition for minima is —————(2)


Therefore, for minima at y, (1) and (2) should be equal.




Here, y=1 mm =0.001m



Now, for n=0,


this is out of range.


Now, for n=1,


which is in range


Now, for n=2,


which is in range


Now, for n=3,


which is out of range.


(b)The highest intensity will be at maxima. For maxima,




Now, for n=1,


which is out of range


Now, for n=2,


which is in range


Now, for n=3,


which is out of range.


Hence maximum intensity would be for


1