CBSE Questions for Class 10 Physics Human Eye And Colorful World Quiz 15 - MCQExams.com

At sun rise of sunset, the sun looks more red than at mid-day because
  • The sun is hottest at these times
  • Of the scattering of light
  • Of the effects of refraction
  • Of the effects of diffraction
A person uses a lens of power $$+3\ D$$ to normalise vision. Near point of hypermetropic eye is 
  • $$1\ m$$
  • $$1.66\ m$$
  • $$2\ m$$
  • $$0.66\ m$$
A person wears glasses of power $$-2.5\ D$$. The defect of the eye and the far point of the person without the glasses are respectively 
  • Farsightedness, $$40\ cm$$
  • Nearsightedness, $$40\ cm$$
  • Astigmatism, $$40\ cm$$
  • Nearsightedness, $$250\ cm$$
To remove myopia ( short sightedness ) a lens of power $$0.66\ D$$ is required. The distant point of the eye is approximately 
  • $$100\ cm$$
  • $$150\ cm$$
  • $$50\ cm$$
  • $$25\ cm$$
Stars are not visible in the day time because
  • Stars hide behind the sun
  • Stars do not reflect sun rays during day
  • Start vanish during the day
  • Atmosphere scatters sunlight into a blanket of extreme
    brightness through which faint stars cannot be visible
The sky would appear red instead of blue if
  • Atmospheric particles scatter blue light more than red light
  • Atmospheric particles scatter all colours equally
  • Atmospheric particles scatter red light more than the blue light
  • The sun was much hotter
Shortsightness eye defect persons cannot see nearby objects.
  • True
  • False
Colour of the sky is blue due to
  • Scattering of light
  • Total internal reflection
  • Total emission
  • None of the above
The band of seven colours that constitute white light is known as
  • Rainbow
  • Palette
  • Spectrum
  • None of these
________ lens is used to correct the defect of vision termed as presbyopia.
  • Convex
  • Concave
  • Bifocal
  • Contact
Which phenomenon does not play a role in the formation of rainbow ?
  • Reflection
  • Refraction
  • Dispersion
  • Absorption
When sunlight enters into an atmosphere, it gets refracted. Because of this atmospheric refraction, virtual image of sun is formed during sunset and sunrise as shown in above diagram. 
Due to this atmospheric refraction, the day __________
1967974_8e3d2af4218441608c48ca60d4430fb8.png
  • becomes four minutes longer than the actual one.
  • becomes four minutes shorter than the actual one.
  • becomes longer in summer and shorter in winter.
  • length of the day can not be said anything.
The sky appears dark to passengers flying at very high altitudes mainly because
  • Scattering of light is not enough at such heights
  • There is no atmosphere at great heights
  • The size of molecules is smaller than the wavelength of visible light
  • The light gets scattered towards the earth
A nearsighted man can clearly object only upto a distance of 100 cm and not beyond this. The number of the spectacles lens necessary for the remedy of this defect will be
  • +1
  • -1
  • +3
  • -3
Rising and setting sun appears to be reddish because:
  • The sun is colder at sunrise or at sunset
  • Diffraction sends red rays to the earth at these times
  • Refraction is responsible for it
  • Scattering due to dust particles and air molecules is responsible for it
A person who can see the nearer objects clearly but not distant objects is suffering from ....................
  • Emnetropia
  • Blindness
  • Myopia
  • None of these
State whether the following statement is True or False. 
You can see a rainbow only when your back is towards the sun
  • True
  • False
A rainbow is formed when the air is:
  •  Full of moisture 
  • Completely Dry
  • Hot 
  • Cold
How is rainbow formed?
  • A result of the absorption of sunlight by the raindrops.
  • A result of the reflection of sunlight by the raindrops.
  • A result of the dispersion of sunlight by the raindrops.
  • A result of the diffraction of sunlight by the raindrops.
Anil, an $$8^{th}$$ grade student, was asked to draw a figure explaining how the mammalian eye collects and focuses light, converting it into electrical signals. Which of the following flow charts correctly represents the process?
  • Light $$\rightarrow$$ Cornea $$\rightarrow$$ Aqueous humor $$\rightarrow$$ Pupil $$\rightarrow$$ Lens $$\rightarrow$$ Vitreous humor $$\rightarrow$$ Retina $$\rightarrow$$ Action potentials in neurons $$\rightarrow$$ Optic nerve $$\rightarrow$$ Brain.
  • Light $$\rightarrow$$ Sclera $$\rightarrow$$ Vitreous humor $$\rightarrow$$ Pupil $$\rightarrow$$ Lens $$\rightarrow$$ Aqueous humor $$\rightarrow$$ Retina $$\rightarrow$$ Action potentials in neurons $$\rightarrow$$ Optic nerve Brain.
  • Light $$\rightarrow$$ Sclera $$\rightarrow$$ Cornea $$\rightarrow$$ Aqueous humor $$\rightarrow$$ Pupil $$\rightarrow$$ Lens $$\rightarrow$$ Vitreous humor $$\rightarrow$$ Retina $$\rightarrow$$ Action potentials in neurons $$\rightarrow$$ Optic nerve $$\rightarrow$$ Brain.
  • Light $$\rightarrow$$ Cornea $$\rightarrow$$ Aqueous humor $$\rightarrow$$ Iris $$\rightarrow$$ Lens $$\rightarrow$$ Vitreous humor $$\rightarrow$$ Retina $$\rightarrow$$ Action potentials in neurons $$\rightarrow$$ Optic nerve $$\rightarrow$$ Brain.
The ciliary muscles of eye control the curvature of the lens in the eye and hence and alter the effective focal length of the system. When the muscles are fully relaxed, the focal length is maximum. When the muscles are strained, the curvature of lens increases. That means, radius of curvature decreases and focal length decreases. For a clear vision, the image must be on the retina. The image distance is therefore fixed for clear vision and it equals the distance of retina from eye lens. It is about $$25\ cm$$ for a grown up person.
A person can theoretically have clear vision of an object situated at any large distance from the eye. The smallest distance at which a person can clearly see is related to minimum possible focal length. The ciliary muscles are most strained in this position. For an average grown up person, minimum distance of the object should be around $$25\ cm$$.
A person suffering from eye defects uses spectacles (eye glass). The function of lens of spectacles is to form the image of the objects within the range in which the person can see clearly. The image of the spectacle lens becomes object for the eye lens and whose image is formed on the retina.
The number of spectacle lens used for the remedy of eye defect is decided by the power of the lens required and the number of spectacle lens is equal to the numerical value of the power of lens with sign. For example, if power of the lens required is $$+3D$$ (converging lens of focal length $$100/3\ cm$$), then number of lens will be $$+3$$.
For all the calculations required, you can used the lens formula and lensmaker's formula. Assume that the eye lens is equiconvex lens. Neglect the distance between the eye lens and the spectacle lens.
A far sighted man cannot see objects clearly unless they are at least $$100 \  cm$$ from his eyes. The number of the spectacle lenses that will make his range of clear vision equal to an average grown up person will be

161180_4cf1606054e54b759ac0662d278d4b97.png
  • $$+1$$
  • $$1$$
  • $$+3$$
  • $$3$$
A man can see objects clearly up to $$3 m$$. What type of lens he should use in order to see clearly up to $$12 m$$?
  • Convex lens, $$f= 4 m$$
  • Concave lens, $$f= 4 m$$
  • Convex lens, $$f= -4 m$$
  • Concave lens, $$f= -4 m$$
The process of re-emission of absorbed light in all directions with different intensities by the atom or molecule is called ____________.
  • Scattering of light
  • Dispersion of light
  • Reflection of light
  • Refraction of light
What is the color of the emergent ray of light when two prisms are placed besides each other in a way that the second is inverted?
  • Red
  • Green
  • White
  • Blue
If red and violet colours are passing through the same glass sheet simultaneously then the relation between their velocities will be:
  • $$v_r\,=\, v_v$$
  • $$v_r\, <\, v_v$$
  • $$v_r\,>\, v_v$$
  • None of these
Sky looks bright from the earth on a sunny day but from any space station it is dark because
  • no reflecting/scattering medium in space
  • no luminous object in space
  • no natural source of light in space
  • eye deficiency
Which of the following are defects of vision?
  • Myopia
  • Hypermetropia
  • Colour blindness
  • Night blindness
A man can see distinctly from a distance of $$0.5 m$$. If he wants to read a book placed at a distance of $$25 cm$$, then what kind of lens should he use?
  • Convex lens with focal length of $$-50 cm$$
  • Concave lens with focal length of $$-50 cm$$
  • Convex lens with focal length of $$50 cm$$
  • Concave lens with focal length of $$50 cm$$
Focal length of eye lens is changes by.
  • Pupil
  • Iris
  • Cornea
  • Ciliary muscles
In Section A, defects of eye are given, in Section B, effects arising due to defects are given and in section C, remedies are given using lenses. Find the correct pair.
Section A
Section B
Section C
Myopia
(x) Focal length increases
(a) Bifocal lens
Hypermetropia
(y)Focal length decreases
(b) Concave lens
Presbyopia
(z) Power of accommodation decreases
(c) Convex lens
  • (1 - y - b), (2 - x - c), (3 - z - a)
  • (1 - z - b), (2 - z - b), (3 - y - b)
  • (1 - x - a), (2 - y - c), (3 - x - a)
  • (1 - y - a), (2 - x - a), (3 - z - c)
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