1
JEE Main 2019 (Online) 10th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
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) ?

JEE Main 2019 (Online) 10th January Evening Slot Physics - Wave Optics Question 122 English
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
$${\lambda \over {\left( {\sqrt 5 - 2} \right)}}$$
2
JEE Main 2019 (Online) 10th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
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
3
JEE Main 2019 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
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
4
JEE Main 2019 (Online) 9th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Consider a tank made of glass(refractive index 1.5) with a thick bottom. It is filled with a liquid of refractive index $$\mu $$. A student finds that, irrespective of what the incident angle i (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarized. For this to happen, the minimum value of $$\mu $$ is :

JEE Main 2019 (Online) 9th January Morning Slot Physics - Wave Optics Question 125 English
A
$$\sqrt {{5 \over 3}} $$
B
$${3 \over {\sqrt 5 }}$$
C
$${5 \over {\sqrt 3 }}$$
D
$${4 \over 3}$$
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