NEET Physics Chapter Wise Mock Test – Wave Optics

NEET Physics Chapter Wise Mock Test – Wave Optics

Question 1:
Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are
(a) 5I and I
(b) 5I and 3I
(c) 9I and I
(d) 9I and 3I

Question 2:
If the equations of two light waves are y₁= 8 sinωt and y₂ = 6 sin(ωt +Φ). Then, ratio of maximum and minimum intensity will be
(a) 11:49
(b) 49:1
(c) 7:1
(d) 1:7

Question 3:
In Young’s double slit experiment, the intensity at a point where the path difference is λ/6 (λ being the wavelength of light used) is I. If I₀ denotes the maximum intensity, I/I₀ is equal to lo
(a) 3/4
(b) 1/√2
(c) √3/2
(d) 1/2

Question 4:
A mixture of light consisting of wavelength 590nm and an unknown wavelength illuminates Young’s double slit and gives rise to two overlapping interference patterns on the screen. The central maximum of both light coincide. Further, it is observed that the third bright fringe is known light coincides with the 4th bright fringe of unknown light. From this idea, the wavelength of unknown light is
(a) 885.0nm
(b) 442.5nm
(c) 776.8nm
(d) 393.4nm

Question 5:
In Young’s double slit experiment, when wavelength used is 6000Å and the screen is 40cm from the slits, the fringes are 0.012 cm wide. What is the distance between the slits?
(a) 0.024m
(b) 2.4m
(c) 0.24m
(d) 0.2m

Question 6:
In Young’s double slit experiment using sodium light (λ=5898Å), 92 fringes are seen. If given colour(λ= 5461Å) is used, how many fringes will be seen?
(a) 62
(b) 67
(c) 85
(d) 99

Question 7:
In a Young’s experiment, two coherent sources are placed 0.90mm apart and the fringes are observed one metre away. If it produces the second dark fringe at a distance of 1mm from the central fringe, then wavelength of monochromatic light used would be
(a) 60×10⁴ cm
(b) 10×10^-4 cm
(c) 10×10^-5 cm
(d) 6×10^-5 cm

Question 8:
In the given figure, Q is the position of first bright range towards right from OP is the position of 5th bright fringe on the other side of O with respect to Q. If wavelength of used light is 6000Å, then value of S₁B will be

(a) 2.4×10^-4 m
(b) 2.4×10^-2 m
(c) 2.4×10^-3 m
(d) 2.4×10^-6 m

Question 9:
In Young’s experiment, two coherent sources are 0.90mm apart and fringes are observed at a distance of 1 m, if 2nd dark fringe is at 1mm distance from central fringe, then wavelength of the monochromatic light will be
(a) 60×10^-4 cm
(b) 10xI0^-4 cm
(c) 10×10^-5 cm
(d) 6×10^-5 cm

Question 10:
In the given figure, C is middle point of line S₁S₂. A monochromatic light of wavelength λ is incident on slits. The ratio of intensity of S₃ and S₄ is

(a) 0
(b) ∞
(c) 4:1
(d) 1:4

Question 11:
In Young’s double slit experiment, one of the slit is covered with a transparent sheet of thickness 3.6×10^-4 cm due to which position of central fringe shifts to a position originally occupied by 30th bright fringe. The refractive index of the sheet, if λ= 6000Å, is
(a) 1.5
(b) 1.2
(c) 1.3
(d) 1.7

Question 12:
In an experiment of double slits, interference fringes are obtained by using light of wavelength 4800Å. If the first slit is covered with a thin sheet of glass having refractive index 1.4 and the second slit is covered with a sheet of same thickness of refractive index 1.7, then the central fringe is displaced to the position of 5th bright fringe. The thickness of glass will be
(a) 10.5×10^-3 mm
(b) 8×10^-3 mm
(c) 6.5×10^-3 mm
(d) 2.5×10^-3mm

Question 13:
Two coherent point sources S₁ and S₂, vibrating in phase emit light of wavelength λ. The separation between them is 2λ. The light is collected on a screen placed at a distance D>>λ from the slit S₁ as shown. The minimum distance, so that intensity at P is equal to intensity at O

(a) √2 D
(b) √3 D
(c) √8 D
(d) √5 D

Question 14:
In Young’s double slit experiment, the spacing between the slits is d and wavelength of light used is 6000Å. If the angular width of a fringe formed on a distant screen is 1°, then value of d is
(a) 1 mm
(b) 0.05 mm
(c) 0.03 mm
(d) 0.01 mm

Question 15:

Question 16:
For the study of the helical structure of nucleic acids,the property of electromagnetic radiation, generally used is
(a) reflection
(b) interference
(c) diffraction
(d) polarisation

Question 17:
A narrow slit S transmitting light of wavelength λ is placed a distance d above a large plane mirror as shown. The light coming directly from the slit and that after reflection interfere at P on the screen placed at a distance D from the slit. What will be x, for which first maxima occurs?

Question 18:
Huygens’ wave theory allows us to know
(a) the wavelength of the wave
(b) the velocity of the wave
(c) the amplitude of the wave
(d) the propagation of wavefronts

Question 19:
What is necessary for easy occurrence of Fresnel’s diffraction?
(a) Obstacle should of the order of wavelength
(b) Narrow opening should be of the order of wavelength
(c) Source and screen should be at finite distance from the obstacle
(d) All of the above

Question 20:
In Fraunhoffer diffraction, the centre of diffraction image is
(a) always bright
(b) always dark
(c) sometimes bright and sometimes dark
(d) bright for large wavelength and dark for low wavelength

Question 21:
For Fraunhoffer single slit diffraction
(a) width of central maxima is proportional to λ
(b) on increasing the slit width, the width of central maxima decreases
(c) on making the slit width a =λ central maxima spreads in the range ±90°
(d) All of the above

Question 22:
Consider the arrangement as shown. The distance D is large compared to d. Minimum value of d, so that there is a dark fringe at O, is

Direction (Q. Nos. 23-26): 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 follows.
(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

Question 23:
Assertion (A): Corpuscular theory fails in explaining the velocities of light in air and water.
Reason (R): According to corpuscular theory, light should travel faster in denser media than in rarer media.

Question 24:
Assertion (A): The unpolarised light and polarised light can be distinguished from each other by using Polaroid.
Reason (R): A polaroid is capable of producing plane polarised beams of light.

Question 25:

Question 26:
Assertion (A): The pattern and position of fringes always remain same even after the introduction of transparent medium in a path of one of the slit.
Reason (R): The central fringe is bright or dark depends upon the initial phase difference between the two coherence sources.

Question 27:
In the Young’s double-slit experiment, the intensity of light at a point on the screen, where the path difference in λ is K (λ, being the wavelength of light used). The intensity at a point, where the path difference is λ/4 will be
(a) K
(b) K/4
(c) K/2
(d) zero

Question 28:
In single slit diffraction pattern
(a) central fringe has negligible width than others
(b) all fringes are of same width
(c) central fringes do not exist
(d) None of the above

Question 29:
For a parallel beam of monochromatic light of wavelength λ, diffraction is produced by a single slit whose width a is of the order of the wavelength of the light. If D is the distance of the screen from the slit, the width of the central maxima will be
(a) 2Dλ/a
(b) Dλ/a
(c) Da/λ
(d) 2Da/λ

Question 30:
In a double slit experiment, the two slits are 1mm apart and the screen is placed 1m away. A monochromatic light of wavelength 50nm is used. What will be the width of each slit for obtaining ten maxima of double slit, within the central maxima of single slit pattern?
(a) 0.2 mm
(b) 0.1 mm
(c) 0.5 mm
(d) 0.02 mm

Question 31:
A beam of light λ=600nm from a distant source, falls on a single slit 1mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between the first dark fringes on other side of the central bright fringe, is
(a) 1.2 cm
(b) 1.2 mm
(c) 2.4 cm.
(d) 2.4 mm

Question 32:
In Young’s double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelength λ₁=12000A and λ₂ =10000Å. At what minimum distance from the common central bright fringe on the screen 2m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other?
(a) 8mm
(b) 6mm
(c) 4mm
(d) 3mm

Question 33:

Question 34:
The ratio of intensity at the centre of a bright fringe to the intensity at a point distance one-fourth of the distance between two successive bright fringes will be
(a) 4
(b) 3
(c) 2
(d) 1

Question 35:
Two beams of light of intensity l₁ and l₂ interfere to give an interference pattern. If the ratio of maximum intensity to that of minimum intensity is 25/9, then l₁/l₂ is
(a) 5/3
(b) 4
(c) 81/625
(d) 16

Question 36:
A telescope consists of two thin lenses of focal lengths 0.3 m and 3cm, respectively. It is focused on moon which subtends an angle of 0.5° at the objective. Then, the angle subtended at the eye by the final image will be
(a) 5°
(b) 0.25°
(c) 0.5°
(d) 0.35°

Question 37:
The Young’s double slit experiment is performed with blue and with green light of wavelengths 4360Å and 5460Å, respectively. If x is the distance of 4th A maxima from the central one, then

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