1
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
2
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
3
JEE Main 2019 (Online) 9th January Morning Slot
+4
-1
Two coherent sources produce waves of different intensities which interfere. After interference, the ratio of the maximum intensity to the minimum intensity is 16. The intensity of the waves are in the ratio :
A
16 : 9
B
25 : 9
C
4 : 1
D
5 : 3
4
JEE Main 2019 (Online) 9th January Morning Slot
+4
-1
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 :

A
$$\sqrt {{5 \over 3}}$$
B
$${3 \over {\sqrt 5 }}$$
C
$${5 \over {\sqrt 3 }}$$
D
$${4 \over 3}$$
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