1
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
The value of numerical aperature of the objective lens of a microscope is 1.25. If light of wavelength 5000 $$\mathop A\limits^o$$ is used, the minimum separation between two points, to be seen as distinct, will be :
A
0.12 $$\mu$$m
B
0.38 $$\mu$$m
C
0.24 $$\mu$$m
D
0.48 $$\mu$$m
2
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
In a double slit experiment, when a thin film of thickness t having refractive index $$\mu$$. is introduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is ($$\lambda$$ is the wavelength of the light used) :
A
$${\lambda \over {2\left( {\mu - 1} \right)}}$$
B
$${\lambda \over {\left( {2\mu - 1} \right)}}$$
C
$${{2\lambda } \over {\left( {\mu - 1} \right)}}$$
D
$${\lambda \over {\left( {\mu - 1} \right)}}$$
3
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
A concave mirror has radius of curvature of 40 cm. It is at the bottom of a glass that has water filled up to 5 cm (see figure). If a small particle is floating on the surface of water, its image as seen, from directly above the glass, is at a distance d from the surface of water. The value of d is dose to: (Refractive index of water = 1.33)
A
11.7 cm
B
6.7 cm
C
13.4 cm
D
8.8 cm
4
JEE Main 2019 (Online) 10th April Evening Slot
+4
-1
In a Young's double slit experiment, the ratio of the slit's width is 4 : 1. The ratio of the intensity of maxima to minima, close to the central fringe on the screen, will be :
A
25 : 9
B
4 : 1
C
$${\left( {\sqrt 3 + 1} \right)^4}:16$$
D
9 : 1
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