1
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
2
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
3
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
$${4 \over 3}$$
4
JEE Main 2018 (Online) 16th April Morning Slot
+4
-1
Unpolarized light of intensity I is incident on a system of two polarizers, A followed by B. The intensity of emergent light is I/2. If a third polarizer C is placed between A and B, the intensity of emergent light is reduced to I/3. The angle between the polarizers A and C is $$\theta$$. Then :
A
cos$$\theta$$ = $${\left( {{2 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 2}}}}$$
B
cos$$\theta$$ = $${\left( {{2 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 4}}}}$$
C
cos$$\theta$$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 2}}}}$$
D
cos$$\theta$$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 4}}}}$$
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