1
WB JEE 2008
+1
-0.25

The radius of curvature of a concave mirror is 24 cm and the image is magnified by 1.5 times. The object distance is

A
20 cm
B
8 cm
C
16 cm
D
24 cm
2
WB JEE 2008
+1
-0.25

A point source of light is kept at a depth of h in water of refractive index 4/3. The radius of the circle at the surface of water through which light emits is

A
$${3 \over {\sqrt 7 }}\,h$$
B
$${{\sqrt 7 } \over 3}\,h$$
C
$${{\sqrt 3 } \over 7}\,h$$
D
$${7 \over {\sqrt 3 }}\,h$$
3
WB JEE 2023
+1
-0.25 Three identical convex lenses each of focal length $$\mathrm{f}$$ are placed in a straight line separated by a distance $$\mathrm{f}$$ from each other. An object is located at f/2 in front of the leftmost lens. Then, A
Final image will be at f/2 behind the rightmost lens and its magnification will be $$-1$$.
B
Final image will be at f/2 behind the rightmost lens and its magnification will be $$+1$$.
C
Final image will be at f behind the rightmost lens and its magnification will be $$-1$$.
D
Final image will be at f behind the rightmost lens and its magnification will be $$+1$$.
4
WB JEE 2022
+1
-0.25 The human eye has an approximate angular resolution of $$\theta$$ = 5.8 $$\times$$ 10$$-$$4 rad and typical photo printer prints a minimum of 300 dpi (dots per inch, 1 inch = 2.54 cm). At what minimal distance d should a printed page be held so that one does not see the individual dots?

A
20.32 cm
B
29.50 cm
C
14.59 cm
D
6.85 cm
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Physics
Mechanics
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Modern Physics
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