1
JEE Main 2019 (Online) 12th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
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A plano-convex lens (focal length f2, refractive index $$\mu $$2, radius of curvature R) fits exactly into a plano-concave lens (focal length f1, refractive index $$\mu $$1, radius of curvature R). Their plane surfaces are parallel to each other. Then, the focal length of the combination will be :
A
f1 + f2
B
f1 $$-$$ f2
C
$${R \over {{\mu _2} - {\mu _1}}}$$
D
$${{2{f_1}{f_2}} \over {{f_1} + {f_2}}}$$
2
JEE Main 2019 (Online) 12th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Formation of real image using a biconvex lens is shown below :

JEE Main 2019 (Online) 12th January Evening Slot Physics - Geometrical Optics Question 146 English

If the whole set up is immersed in water without disturbing the object and the screen positions, what will one observe on the screen ?
A
Image disappears
B
Magnified image
C
Erect real image
D
No change
3
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
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A point source of light, S is placed at distance L in front of the centre of plane mirror of width d which is hanging vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror, at a distance 2L as shown below. The distance over which the man can see the image of the light source in the mirror is

JEE Main 2019 (Online) 12th January Morning Slot Physics - Geometrical Optics Question 149 English
A
d
B
d/2
C
3d
D
2d
4
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
What is the position and nature of image formed by lens combination shown in figure ? (f1, f2 are focal lengths)

JEE Main 2019 (Online) 12th January Morning Slot Physics - Geometrical Optics Question 148 English
A
$${{20} \over 3}$$ cm from point B at right, real
B
70 cm from point B at right ; real
C
40 cm from point B at right; real
D
70 cm from point B at left ; virtual
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