1
JEE Main 2018 (Online) 16th April Morning Slot
+4
-1
A ray of light is incident at an angle of 60o on one face of a prism of angle 30o. The emergent ray of light makes an angle of 30o with incident ray. The angle made by the emergent ray with second face of prism will be :
A
0o
B
90o
C
45o
D
30o
2
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$$\theta$$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{\scriptstyle 1} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 4}}}}$$
3
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
4
JEE Main 2018 (Offline)
+4
-1
Unpolarized light of intensity I passes through an ideal polarizer A. Another identical polarizer B is placed behind A. The intensity of light beyond B is found to be I/2. Now another identical polarizer C is placed between A and B. The intensity beyond B is now found to be I/8. The angle between polarizer A and C is :
A
60o
B
30o
C
45o
D
0o
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