NEET Physics Chapter Wise Mock Test – Ray Optics
A ray of light is successively deflected from two plane mirrors inclined to each other at a certain angle. If the total deviation in the path of the rays reflected from the two mirrors be 300°, then what is the number of images formed?
A concave mirror forms the real image of an object which is magnified 4 times. The object is moved 3 cm away, the magnification of the image is 3 times. What is the focal length of the mirror?
A room (cubical) is made of mirrors. An insect is moving along the diagonal on the floor, such that the velocity of image of insect on two adjacent wall mirrors, is 10 cms-1. The velocity of image of insect in ceiling mirror is
(a) 10 cms-1
(b) 20 cms-1
(c) 10/√2 cms-1
(d) 10√2 cms-1
The image formed by a convex mirror of focal length 30 cm is a quarter of the size of the object. The distance of the object from the mirror is
(a) 30 cm
(c) 120 cm
A convex lens and a concave lens, each having same focal length of 25 cm, are put in contact to form a combination of lenses. The power in dioptres of the combination is
In the given figure, the angle of reflection is
(d) None of these
A glass slab (μ= 1.5) of thickness 6 cm is placed over a paper. What is the shift in the letters?
(d) None of these
A 4cm thick layer of water covers a 6 cm thick glass slab. A coin is placed at the bottom of the slab and is being observed from the air side along the normal to the surface. Find the apparent position of the coin from
A student measures the focal length of a convex lens by putting an object pin at a distance u from the lens, and measuring the distance v of the image pin. The graph between u and v plotted by the student should look like.
A microscope is focussed on a mark on a piece of paper and then, a slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?
(a) 1cm upward
(b) 4.5cm downward
(c) 1cm downward
(d) 2cm upward
A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and m3oves along its surface as shown in figure.
How fast is the light travelling in the liquid?
(a) 1.8x 108 ms-1
(b) 2.4x 108 ms-1
(c) 3.0 x 108 ms-1
(d) 1.2x 104 ms-1
The frequency of a light wave in a material is 2X1014 HZ and wavelength is 5000Å. The refractive index of material will be
A lens has focal length 10 cm. An object is placed 15 cm in front of it. Where should a convex mirror be placed, so that image is formed at the object itself, when focal length of convex mirror is 12 cm?
(a) 6cm from lens
(b) 8cm from lens
(c) 5cm from lens
(d) 4cm from lens
If in a plano-convex lens, radius of curvature of convex surface is 10 cm and the focal length of the lens is 30 cm, the refractive index of the material of the lens will be
The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it will
(a) act as a convex lens only for the objects that lie on its curved side
(b) act as a concave lens for the objects that lie on its curved side
(c) act as a convex lens irrespective of the side, on which the object lies
(d) act as a concave lens irrespective of side, on which the object lies
For an optical arrangement as shown in the figure. Find the position and nature of image.
(a) 32 cm
(b) 0.6 cm
(c) 6 cm
(d) 0.5 cm
A thin plano-convex lens of focal length f is split into two halves. One of the halves is shifted along the optical axis. The separation between object and image plane is 1.8 m. The magnification of the image formed by one of the half lens is 2. Find the focal-length of the lens and separation between the two halves.
A thin convergent glass lens (μ= 1.5) has a power of + 5.0 D. When this lens is immersed in a liquid of refractive index μl, it acts as a divergence lens of focal length 100 cm. The value of μl, should be
The distance of the image from the focus of a lens is x and that of object is y. What is the nature of the graph y versus x?
(a) Straight line
Two lamps of powers P1 and P2 are placed on either side of a paper having an oil spot. The lamps are at 1m and 2 m respectively, on either side of the paper and the oil spot is invisible. What is the value of P1/P2 ?
If the critical angle for total internal reflection from a medium to vacuum is 30°, the velocity of light in the medium is
(a) 3×108 ms-1
(b) 1.5 x 108 ms-1
(c) 6×108 ms-1
(d) √3 x 108 ms-1
A glass prism ABC (refractive index 1.5), immersed in water (refractive index 4/3). A ray of light is incident normally on face AB. If it is totally reflected at face AC, then
A thin prism of angle 7° and refractive index 1.5 is combined with another prism of angle θ and refractive index 1.7. The emergent ray goes undeviated. What is the value of 0?
A thin glass prism (μ= 1.5) is immersed in water (μ= 1.3). If the angle of deviation in air for a particular ray be D, then that in water will be
(a) 0.2 D
A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence is
The refractive index of the material of a prism is √2 and its refracting angle is 30°. One of the refracting surfaces of the prism is made a mirror inwards. A beam of monochromatic light entering the prism from the other face will retrace its path after reflection from the mirrored surface, if its angle of incidence on the prism is
To correct myopia, the focal length of the concave lens should be .
(a) equal to the distance of far point
(b) less than the distance of far point
(c) less than the distance of near point
(d) equal to the distance of near point
A simple telescope, consisting of an objective of focal length 60 cm and a single eye lens of focal length 5 cm is focused on a distant object in such a way that parallel rays emerge from the eye lens. If the object subtends an angle of 2° at the objective, the angular width of the image is
The diameter of the moon is 3.5x 103 km and its distance from the earth is 3.8 x 105 km. Seen by a telescope having focal lengths of the objective and the eye piece as 40 mm and 1.0 cm respectively, the angular diameter of the image of the moon will be approximately
(d) None of these
Direction (Q. Nos. 31-34): In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as
(a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
(b) If both Assertion and Reason are true but the Reason is not correct explanation of the Assertion
(c) If Assertion is true but Reason is false
(d) If both Assertion and Reason are false
Assertion (A): A short sighted person cannot see objects clearly, when placed beyond 50 cm. He should use a concave lens of power 2D.
Reason (R): Concave lens should form image of an object at infinity placed at a distance of 50 cm.
Assertion (A): Angle of deviation depends on the angle of prism.
Reason (R): For thin prism, δ= (μ-1)A
where, δ= angle of deviation
μ= refractive index
A = angle of prism
Assertion (A): The mirrors used in search lights are parabolic and not concave spherical.
Reason (R): In a concave spherical mirror, the image formed is always virtual.
Assertion (A): Glass is transparent but its powder seems opaque. When water is poured over it, it becomes transparent.
Reason (R): Light gets refracted through water.
The refracting angle of a prism is A and refractive index of the material of the prism is cot(A/2). The angle of minimum deviation is
(b) 180°-2 A
(c) 90°- A
A lens, when placed on a plane mirror, then object needle and its image coincide at 15 cm. The focal length of the lens is
A hollow prism is filled with water and placed in air. It will deviate the incident rays
(a) towards the base
(b) away from base
(c) parallel to base
(d) towards or away from base depending on the location
In a compound microscope, the intermediate image is
(a) virtual, erect and magnified
(b) real, erect and magnified
(c) real, inverted and magnified
(d) virtual, erect and reduced
A convex lens has mean focal length 20cm. The dispersive power of the material of the lens is 0.02. The longitudinal chromatic aberration for an object at infinity is
For a normal eye, the cornea of eye provides a converging power of 40D and the least converging power of the eye lens behind the cornea is 20D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be
Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. The focal length of the combination is
(a) -20 cm
(b) -25 cm
(c) -50 cm .
(d) 50 cm
The angle of a prism is A. One of its refracting
(a) 2 sinA
(b) 2 cosA
(c) 1/2 cosA
The focal length of objective lens is increased then magnifying power of
(a) Microscope will increase but that of telescope decrease
(b) Microscope and telescope both will increase
(c) Microscope and telescope both will decrease
(d) Microscope will decrease but that of telescope will increase
What is the refractive index of a prism whose angle A=60° and angle of minimum deviation dm = 30°?
A thin prism P1 of angle 4° and refractive index 1.54° is combined with another thin prism P2 of refractive index 1.72 to produce dispersion without deviation. The angle of P2 is
Which of the following is not due to total internal reflection?
(a) Difference between apparent and real depth of a pond
(b) Mirage on hot summer days
(c) Brilliance of diamond
(d) Working of optical fibre
A ray of light travelling in a transparent medium of refractive index μ falls, on a surface separating the medium from air at an angle of incidence of 45°. For which of the following value of mu the ray can undergo total internal reflection?
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