1
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
2
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
$${4 \over 3}$$
3
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$$\theta$$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 4}}}}$$
4
JEE Main 2018 (Offline)
+4
-1
The angular width of the central maximum in a single slit diffraction pattern is 60°. The width of the slit is 1 $$\mu$$m. The slit is illuminated by monochromatic plane waves. If another slit of same width is made near it, Young’s fringes can be observed on a screen placed at a distance 50 cm from the slits. If the observed fringe width is 1 cm, what is slit separation distance? (i.e. distance between the centres of each slit.)
A
100 $$\mu$$m
B
25 $$\mu$$m
C
50 $$\mu$$m
D
75 $$\mu$$m
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