1
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
In a Young's double slit experiment, the path difference, at a certain point on the screen, between two interfering waves is $${1 \over 8}$$ th of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to :
A
0.94
B
0.85
C
0.74
D
0.80
2
JEE Main 2019 (Online) 10th January Evening Slot
+4
-1
Consider a Young’s double slit experiment as shown in figure. What should be the slit separation d in terms of wavelength $$\lambda$$ such that the first minima occurs directly in front of the slit (S1) ?

A
$${\lambda \over {2\left( {5 - \sqrt 2 } \right)}}$$
B
$${\lambda \over {2\left( {\sqrt 5 - 2} \right)}}$$
C
$${\lambda \over {\left( {5 - \sqrt 2 } \right)}}$$
D
$${\lambda \over {\left( {\sqrt 5 - 2} \right)}}$$
3
JEE Main 2019 (Online) 10th January Morning Slot
+4
-1
In a Young’s double slit experiment with slit separation 0.1 mm, one observes a bright fringe at angle $${1 \over {40}}$$ by using light of wavelength $$\lambda$$1. When the light of wavelength $$\lambda$$2 is used a bright fringe is seen at the same angle in the same set up. Given that $$\lambda$$1 and $$\lambda$$2 are in visible range (380 nm to 740 nm), their values are -
A
400 nm, 500 nm
B
625 nm, 500 nm
C
380 nm, 500 nm
D
380 nm, 525 nm
4
JEE Main 2019 (Online) 9th January Evening Slot
+4
-1
In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength $$\lambda$$ = 500 nm is incident on the slits. The total number of bright fringes that are observed in the angular range $$-$$ 30o$$\le$$$$\theta$$$$\le$$30o is :
A
640
B
320
C
321
D
641
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