-
question_answer1)
A concave mirror is placed at the bottom of an empty tank with face upwards and axis vertical. When sunlight falls normally on the mirror, it is focussed at distance of 32 cm from the mirror. If the tank filled with Water \[\left( \mu =\frac{4}{3} \right)\] up to a height of 20 cm, then the sunlight will now get focused at
A)
16 cm above water level done
clear
B)
9 cm above water level done
clear
C)
24 cm below water level done
clear
D)
9 cm below water level done
clear
View Solution play_arrow
-
question_answer2)
The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image
A)
1.25 cm done
clear
B)
2.5 cm done
clear
C)
1.05 cm done
clear
D)
2 cm done
clear
View Solution play_arrow
-
question_answer3)
A point object is placed at a distance of 10 cm and its real image is formed at a distance of 20 cm from a concave mirror. If the object is moved by 0.1 cm towards the mirror, the image will shift by about
A)
0.4 cm away from the mirror done
clear
B)
0.4 cm towards the mirror done
clear
C)
0.8 cm away from the mirror done
clear
D)
0.8 cm towards the mirror done
clear
View Solution play_arrow
-
question_answer4)
The graph shows variation of v with change in u for a mirror. Points plotted above the P point on the curve are for values of v
A)
Smaller than\[f\] done
clear
B)
Smaller than\[2f\] done
clear
C)
Larger than \[2f\] done
clear
D)
Larger than\[f\] done
clear
View Solution play_arrow
-
question_answer5)
A beam of light propagates through medium 1 and falls onto another medium 2, at an angle \[{{\alpha }_{1}}\] as shown in figure. After that, it propagates in Medium 2 at an angle \[{{\alpha }_{2}}\] as shown. The light's wavelength in medium 1 is \[{{\lambda }_{1}}\]. What is the wavelength of light in medium 2?
A)
\[\frac{\sin \,{{\alpha }_{1}}}{\sin {{\alpha }_{2}}}{{\lambda }_{1}}\] done
clear
B)
\[\frac{\sin \,{{\alpha }_{2}}}{\sin {{\alpha }_{1}}}{{\lambda }_{1}}\] done
clear
C)
\[\frac{\cos \,{{\alpha }_{1}}}{\cos {{\alpha }_{2}}}{{\lambda }_{1}}\] done
clear
D)
\[\frac{\cos \,{{\alpha }_{2}}}{\cos {{\alpha }_{1}}}{{\lambda }_{1}}\] done
clear
View Solution play_arrow
-
question_answer6)
Consider the situation shown in figure. Water \[(\mu =4/3)\] is filled in a beaker upto a height of 10 cm. A plane mirror is fixed at a height of 5 cm from the surface of water. Distance of image from the mirror after reflection from it of an object 0 at the bottom of the beaker is
A)
15 cm done
clear
B)
12.5 cm done
clear
C)
7.5 cm done
clear
D)
10 cm done
clear
View Solution play_arrow
-
question_answer7)
Critical angle of glass is\[{{\theta }_{1}}\]and that of water is\[{{\theta }_{2}}\]. The critical angle for water and glass surface would be \[({{\mu }_{g}}=3/2,{{\mu }_{w}}=4/3)\]
A)
Less than\[{{\theta }_{2}}\] done
clear
B)
Between \[{{\theta }_{1}}\] and\[{{\theta }_{2}}\] done
clear
C)
Greater than \[{{\theta }_{2}}\] done
clear
D)
Less than \[{{\theta }_{1}}\] done
clear
View Solution play_arrow
-
question_answer8)
A ray of light is incident on a glass sphere of refractive index 3/2. What should be the angle of incidence so that the ray which enters the sphere does not come out of the sphere?
A)
\[te{{n}^{-1}}(2/3)\] done
clear
B)
\[{{60}^{0}}\] done
clear
C)
\[{{90}^{0}}\] done
clear
D)
\[{{30}^{0}}\] done
clear
View Solution play_arrow
-
question_answer9)
A lens forms a real image of an object. The distance from the object to the lens is x cm and that from the lens to the image is y cm. The graph (see figure) shows the variation of y with x. It can be deduced that the lens is
A)
Converging and of focal length 10 cm done
clear
B)
Converging and of focal length 20 cm done
clear
C)
Converging and of focal length 40 cm done
clear
D)
Diverging and of focal length 20 cm done
clear
View Solution play_arrow
-
question_answer10)
Consider an equiconvex lens of radius of curvature R and focal length\[f.\,\]If \[f>R\,\], the refractive index \[\mu \]of the material of the lens
A)
Is greater than zero but less than 1.5 done
clear
B)
Is greater than 1.5 but less than 2.0 done
clear
C)
Is greater than 1.0 but less than 1.5 done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer11)
A point object is placed at a distance of 25 cm from a convex lens of focal length 20 cm. If a glass slab of thickness t and refractive index 1.5 is inserted between the lens and the object, the image is formed at infinity. The thickness t is
A)
10 cm done
clear
B)
5 cm done
clear
C)
20 cm done
clear
D)
15 cm done
clear
View Solution play_arrow
-
question_answer12)
Two convex lenses placed in contact form the image of a distant object at P. If lens is moved to the right, the image will
A)
Move to the left done
clear
B)
Move to the right done
clear
C)
Remain at P done
clear
D)
Move either to the left or right, depending upon focal lengths of the lenses. done
clear
View Solution play_arrow
-
question_answer13)
A convex lens of focal length 1.0 m and a concave lens of focal length 0.25 m are 0.75 m apart. A parallel beam of light is incident on the convex lens. The beam emerging after refraction from both lenses is
A)
Parallel to the principal axis done
clear
B)
Convergent done
clear
C)
Divergent done
clear
D)
None of the above done
clear
View Solution play_arrow
-
question_answer14)
A light ray is incident by grazing one of the face of a prism and after refraction ray does not emerge out, what should be the angle of prism while critical angle is C?
A)
Equal to 2C done
clear
B)
Less than 1C done
clear
C)
More than 2C done
clear
D)
None of the above done
clear
View Solution play_arrow
-
question_answer15)
A prism of refractive index \[\mu \] and angle A is placed in the minimum deviation position. If the angle of minimum deviation is A, then the value of A in terms of\[\mu \] is
A)
\[{{\sin }^{-1}}\left( \frac{\mu }{2} \right)\] done
clear
B)
\[{{\sin }^{-1}}\sqrt{\frac{\mu -1}{2}}\] done
clear
C)
\[2{{\cos }^{-1}}\left( \frac{\mu }{2} \right)\] done
clear
D)
\[{{\cos }^{-1}}\left( \frac{\mu }{2} \right)\] done
clear
View Solution play_arrow
-
question_answer16)
The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is 54 cm. The focal length of eye lens and objective lens will be respectively
A)
6 cm and 48 cm done
clear
B)
48 cm and 6 cm done
clear
C)
8 cm and 64 cm done
clear
D)
64 cm and 8 cm done
clear
View Solution play_arrow
-
question_answer17)
A telescope of diameter 2 m uses light of wavelength 5000 A for viewing stars. The minimum angular separation between two stars whose image is just resolved by this telescope is
A)
\[4\times {{10}^{-4}}\]rad done
clear
B)
\[0.25\times {{10}^{-6}}\]rad done
clear
C)
\[0.31\times {{10}^{-6}}\]rad done
clear
D)
\[5.0\times {{10}^{-3}}\]rad done
clear
View Solution play_arrow
-
question_answer18)
A fish is vertically below a flying bird moving vertically= down towards water surface. The bird will appear to the fish to be
A)
Moving faster than its speed and also away from the real distance done
clear
B)
Moving faster than its real speed and nearer than its real distance done
clear
C)
Moving slower than its real speed and also nearer than its real distance done
clear
D)
Moving slower than its real speed and away from the real distance done
clear
View Solution play_arrow
-
question_answer19)
Light is incident normally on face AB of a prism as shown in figure; A liquid of refractive index \[\mu \] is placed on face AC of the prism, the prism is made of glass of refractive index 3/2.
The limits of \[\mu \] for which total internal reflection takes place on face AC is
A)
\[\mu >\frac{3}{4}\] done
clear
B)
\[\mu <\frac{3}{4}\] done
clear
C)
\[\mu >\sqrt{3}\] done
clear
D)
\[\mu <\frac{\sqrt{3}}{2}\] done
clear
View Solution play_arrow
-
question_answer20)
A rectangular glass slab ABCD, of refractive index \[{{n}_{1}}\] is immersed in water of refractive index\[{{n}_{2}}({{n}_{1}}>{{n}_{2}})\]. A ray of light in incident at the surface AB of the slab as shown. The maximum value of the angle of incidence\[{{\alpha }_{\max }}\] such that the ray comes out only from the other surface CD is given by
A)
\[{{\sin }^{-1}}\left[ \frac{{{n}_{1}}}{{{n}_{2}}}\cos \left( {{\sin }^{-1}}\frac{{{n}_{2}}}{{{n}_{1}}} \right) \right]\] done
clear
B)
\[{{\sin }^{-1}}\left[ {{n}_{1}}\cos \left( {{\sin }^{-1}}\frac{1}{{{n}_{2}}} \right) \right]\] done
clear
C)
\[{{\sin }^{-1}}\left( \frac{{{n}_{1}}}{{{n}_{2}}} \right)\] done
clear
D)
\[{{\sin }^{-1}}\left( \frac{{{n}_{2}}}{{{n}_{1}}} \right)\] done
clear
View Solution play_arrow
-
question_answer21)
An object 2.4 m in front of a lens forms a sharp image on a film 12 cm behind the lens. A glass plate 1 cm thick, of refractive index 1.50, is interposed between lens and film with its plane faces parallel to film. At what distance (in m) from lens should object shifted to be in sharp focus on film?
View Solution play_arrow
-
question_answer22)
A fish looking up through water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12 cm below the surface, the radius of this circle (in cm) is _______.
View Solution play_arrow
-
question_answer23)
Behind a thin converging lens having both the surfaces of the same radius 10 cm, a plane mirror has been placed. The image of an object at a distance of 40 cm from the lens is formed at the same position. What is the refractive index of the lens?
View Solution play_arrow
-
question_answer24)
A ray of light enters a rectangular glass slab of refractive index\[\sqrt{3}\]at an angle of incidence\[60{}^\circ \]. It travels a distance of 5 cm inside the slab and emerges out of the slab. The perpendicular distance (in cm) between the incident and the emergent rays is ____.
View Solution play_arrow
-
question_answer25)
A convex lens of focal length 20 cm and a concave lens of focal length\[f\]are mounted coaxially 5 cm apart. Parallel beam of light incident on the convex lens emerges from the concave lens as a parallel beam. Then, \[f\] (in cm) is
View Solution play_arrow