1
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
2
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
3
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
A plane polarized light is incident on a polariser with its pass axis aking angle $$\theta$$ with x-axis, as shown in the figure. At four different values of $$\theta ,\,\theta$$ = 8o, 38o, 188o and 218o, the observed intensities are same.
What is the angle between the direction of polarization and x-axis ?
A
98o
B
128o
C
203o
D
45o
4
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
A convergent doublet of separated lenses, corrected for spherical aberration, has resultant focal length of 10 cm. The separation between the two lenses is $$2$$ cm. The focal lengths of the component lenses are :
A
10 cm, 12 cm
B
12 cm, 14 cm
C
16 cm, 18 cm
D
18 cm, 20cm
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