JEE Questions for Physics Ray Optics Quiz 15 - MCQExams.com

In the formation of primary rainbow, the sunlight rays emerge at minimum deviation from rain-drop after
  • One internal reflection and one refraction
  • One internal reflection and two refractions
  • Two internal reflections and one refraction
  • Two internal reflections and two refractions
Dispersive power depends upon
  • The shape of prism
  • Material of prism
  • Angle of prism
  • Height of the prism
When white light passes through the achromatic combination of prisms, then what is observed
  • Only deviation
  • Only dispersion
  • Deviation and dispersion
  • None of the above
The dispersion for a medium of wavelength λ is D, then the dispersion for the wavelength 2λ will be
  • D/8
  • D/4
  • D/2
  • D
The ratio of angle of minimum deviation of a prism in air and when dipped in water will be (aμg = 3 / 2 and (aμw = 4/ 3?
  • 1/8
  • 1/2
  • 3/4
  • 1/4
The respective angles of the flint and crown glass prisms are A\' and A. They are to be used for dispersion without deviation, then the ratio of their angles A\'/ A will be

  • Physics-Ray Optics-86154.png
  • 2)
    Physics-Ray Optics-86155.png

  • Physics-Ray Optics-86156.png

  • Physics-Ray Optics-86157.png
The no. of wavelengths in the visible spectrum
  • 4000
  • 6000
  • 2000
  • Infinite
The black lines in the solar spectrum during solar eclipse can be explained by
  • Planck's law
  • Kirchhoff’s law
  • Boltzmann's law
  • Solar disturbances
The dispersive power is maximum for the material
  • Flint glass
  • Crown glass
  • Mixture of both
  • None of these
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
  • Equal to 2C
  • Less than 2C
  • More than 2C
  • None of these
A parallel beam of monochromatic light is incident at one surface of an equilateral prism. Angle of incidence is 55° and angle of emergence is 46°. The angle of minimum deviation will be
  • Less than 41°
  • Equal to 41°
  • More than 41°
  • None of these
The spectrum of light emitted by a glowing solid is
  • Continuous spectrum
  • Line spectrum
  • Band spectrum
  • Absorption spectrum
Light rays from a source are incident on a glass prism of index of refraction μ and angle of prism α. At near normal incidence, the angle of deviation of the emerging rays is
  • (μ – 2 )α
  • (μ – 1 )α
  • (μ + 1 )α
  • (μ + 2 )α
Which of the following element was discovered by study of Fraunhoffer lines
  • Hydrogen
  • Oxygen
  • Helium
  • Ozone
By placing the prism in minimum deviation position, images of the spectrum
  • Becomes inverted
  • Becomes broader
  • Becomes distinct
  • Becomes intensive
Our eye is most sensitive for which of the following wavelength
  • 4500 Å
  • 5500 Å
  • 6500 Å
  • Equally sensitive for all wave lengths of visible spectrum
Three prisms of crown glass, each have angle of prism 9° and two prisms of flint glass are used to make direct vision spectroscope. What will be the angle of flint glass prisms if μ for flint is 1.60 and μ for crown glass is 1.53
  • 11.9°
  • 16.0°
  • 15.3°
  • 9.11°
If the refractive indices of crown glass for red, yellow and violet colours are 1.5140, 1.5170 and 1.5318 respectively and for flint glass these are 1.6434, 1.6499 and 1.6852 respectively, then the dispersive powers for crown and flint glass are respectively
  • 0.034 and 0.064
  • 0.064 and 0.034
  • 1.00 and 0.064
  • 0.034 and 1.0
The minimum temperature of a body at which it emits light is
  • 1200°C
  • 1000°C
  • 500°C
  • 200°C
Band spectrum is obtained when the source emitting light is in the form of
or
Band spectrum is characteristic of
  • Atoms
  • Molecules
  • Plasma
  • None of these
In the position of minimum deviation when a ray of yellow light passes through the prism, then its angle of incidence is
  • Less than the emergent angle
  • Greater than the emergent angle
  • Sum of angle of incidence and emergent angle is 90°
  • Equal to the emergent angle
A circular disc of which 2/3 part is coated with yellow and 1/3 part is with blue. It is rotated about its central axis with high velocity, then it will be seen as
  • Green
  • Brown
  • White
  • Violet
The fine powder of a coloured glass is seen as
  • Coloured
  • White
  • That of the glass colour
  • Black
When a white light passes through a hollow prism, then
  • There is no dispersion and no deviation
  • Dispersion but no deviation
  • Deviation but no dispersion
  • There is dispersion and deviation both
Continuous emission spectrum is produced by
  • Incandescent electric lamp
  • Mercury vapor lamp
  • Sodium vapor lamp
  • The Sun
A prism of a certain angle deviates the red and blue rays by 8° and 12° respectively. Another prism of the same angle deviates the red and blue rays by 10° and14° respectively. The prisms are small angled and made of different materials. The dispersive powers of the materials of the prisms are in the ratio
  • 5 : 6
  • 9 : 11
  • 6 : 5
  • 11 : 9
If the refractive indices of a prism for red, yellow and violet colours be 1.61, 1.63 and 1.65 respectively, then the dispersive power of the prism will be

  • Physics-Ray Optics-86169.png
  • 2)
    Physics-Ray Optics-86170.png

  • Physics-Ray Optics-86171.png

  • Physics-Ray Optics-86172.png
In fog, photographs of the objects taken with infrared radiations are more clear than those obtained duringvisible light because
  • I-R radiation has lesser wavelength than visible radiation
  • Scattering of I-R light is more than visible light
  • The intensity of I-R light from the object is less
  • Scattering of I-R light is less than visible light
Minimum deviation is observed with a prism having angle of prism A, angle of deviation δ, angle of incidence i and angle of emergence e. We then have generally
  • i > e
  • i < e
  • i = e
  • i = e = δ
An achromatic prism is made by combining two prisms P1 (μv =1.523, μr = 1.and P2 (μv = 1.666, μr = 1.; where μ represents the refractive index. If the angle of the prism P1 is 10°, then the angle of the prism P2 will be
  • 5°
  • 7.8°
  • 10.6°
  • 20°
If the ratio of amounts of scattering of two light waves is 1:4, the ratio of their wavelength is
  • 1 : 2
  • 2)
    Physics-Ray Optics-86176.png

  • Physics-Ray Optics-86177.png
  • 1 : 1
The band spectra (characteristic of molecular species) is due to emission of radiation
  • Gaseous state
  • Liquid state
  • Solid state
  • All of three states
Beams of red, green and violet light are falling on the refracting face of a prism, all at the same angle of incidence, if their angles of deviation are θ1, θ2 and θ3respectively, then
  • θ1 = θ2 = θ3
  • θ1< θ2< θ3
  • θ1> θ2> θ3
  • θ2> θ1> θ3
The spectrum of iodine gas under white light will be
  • Only violet
  • Bright lines
  • Only red lines
  • Some black bands in continuous spectrum
A medium is said to be dispersive, if
  • Light of different wavelengths propagate at different speeds
  • Light of different wavelengths propagate at same speed but has different frequencies
  • Light is gradually bent rather than sharply refracted at an interface between the medium and air
  • Light is never totally internally reflected
A ray of light is incident at an angle of 60° on one face of a prism of angle 30°. The ray emerging out of the prism makes an angle of 30° with the incident ray. The emergent ray is
  • Normal to the face through which it emerges
  • Inclined at 30° to the face through which it emerges
  • Inclined at 60° to the face through which it emerges
  • None of the above
In a thin prism of glass (refractive index 1.5), which of the following relations between the angle of minimum deviations δm and angle of refraction r will be correct
  • δm = r
  • δm = 1.5 r
  • δm = 2r
  • δm = r/2
The figures represent three cases of a ray passing through a prism of angle A. The case corresponding to minimum deviation is
Physics-Ray Optics-86182.png
  • 1
  • 2
  • 3
  • None of these
Dispersion can take place for
  • Transverse waves only but not for longitudinal waves
  • Longitudinal waves only but not for transverse waves
  • Both transverse and longitudinal waves
  • Neither transverse nor longitudinal waves
Emission spectrum of CO2 gas
  • Is a line spectrum
  • Is a band spectrum
  • Is a continuous spectrum
  • Does not fall in the visible region
A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal tothe angle of emergence and each of these angles is equal to 3/4 of the angle of the prism. The angle of deviation is
  • 45°
  • 39°
  • 20°
  • 30°
A beam of light consisting of red, green and blue colours is incident on a right-angled prism ABC. The refractive indices of the material of the prism for the above red, green and blue wavelengths are 1.39, 1.44 and 1.47 respectively. The colour/colours transmitted through the face AC of the prism will be
Physics-Ray Optics-86184.png
  • Red only
  • Red and green
  • All the three colours
  • None of these
When light emitted by a white hot solid is passed through a sodium flame, the spectrum of the emergent light will show
  • The D1 and D2 bright yellow lines of sodium
  • Two dark lines in the yellow region
  • All colours from violet to red
  • No colours at all
A prism ABC of angle 30° has its face AC silvered. A ray of light incident at an angle of 45° at the face AB retraces its path after refraction at face AB and reflection at face AC. The refractive index of the material of the prism is
Physics-Ray Optics-86186.png
  • 1.5
  • 2)
    Physics-Ray Optics-86187.png

  • Physics-Ray Optics-86188.png
  • 4/3
A light ray is incident upon a prism in minimum deviation position and suffers a deviation of 34°. If the shaded half of the prism is knocked off, the ray will
Physics-Ray Optics-86190.png
  • Suffer a deviation of 34°
  • Suffer a deviation of 68°
  • Suffer a deviation of 17°
  • Not come out of the prism
A ray of monochromatic light is incident on one refracting face of a prism of angle 75°. It passes through the prism and is incident on the other face at the critical angle. If the refractive index of the material of the prism is √2 the angle of incidence on the first face of the prism is
  • 30°
  • 45°
  • 60°
  • 0°
Three glass prisms A, B and C of same refractive index are placed in contact with each other as shown in figure, with no air gap between the prisms. Monochromatic ray of light OP passes through the prism assembly and emerges as QR. The conditions of minimum deviation is satisfied in the prisms
Physics-Ray Optics-86193.png
  • A and C
  • B and C
  • A and B
  • In all prisms A, B and C
The refractive index of a material of a prism of angles 45°– 45° – 90° is 1.5. The path of the ray of light incident normally on the hypotenuse side is shown in

  • Physics-Ray Optics-86194.png
  • 2)
    Physics-Ray Optics-86195.png

  • Physics-Ray Optics-86196.png

  • Physics-Ray Optics-86197.png
Angle of deviation (δ) by a prism (refractive index = μ and supposing the angle of prism A to be small) can be given by

  • Physics-Ray Optics-86198.png
  • 2)
    Physics-Ray Optics-86199.png

  • Physics-Ray Optics-86200.png

  • Physics-Ray Optics-86201.png
Angle of prism is A and its one surface is silvered. Light rays falling at an angle of incidence 2A on first surface return back through the same path after suffering reflection at second silvered surface. Refractive index of the material of prism is
  • 2 sin A
  • 2 cos A
  • 1/2 cos A
  • tan A
0:0:1


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