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❓ Chapter Important Questions
नीचे दिए गए questions को chapter के major concepts के
अनुसार arrange किया गया है। इसमें very short answer,
short answer, long answer, reasoning, diagram-based,
competency-based और application-oriented questions
शामिल हैं।
🎯 Exam Tip:
Human eye diagrams, defects of vision, atmospheric
refraction, dispersion, scattering और natural phenomena
से जुड़े “Why” questions को explanation के साथ तैयार करें।
CBSE competency resources भी इस chapter में explanation,
interpretation, labelled diagrams और application-oriented
assessment को include करते हैं. :contentReference[oaicite:1]{index=1}
Section A – Very Short Answer Questions
Q1
What is the function of the iris?
The iris controls the size of the pupil and
therefore regulates the amount of light entering
the eye.
Q2
What is the function of the retina?
The retina is the light-sensitive layer on which
the image of an object is formed.
Q3
What is power of accommodation?
It is the ability of the eye lens to adjust its
focal length so that objects at different
distances can be seen clearly.
Q4
What is the near point of a normal human eye?
The near point of a normal young adult eye is
approximately 25 cm.
Q5
What is myopia?
Myopia is a defect of vision in which distant
objects are not seen clearly.
Q6
Which lens is used to correct myopia?
A suitable concave lens is used to correct myopia.
Q7
Which lens is used to correct hypermetropia?
A suitable convex lens is used to correct hypermetropia.
Q8
What is dispersion of light?
Dispersion is the splitting of white light into
its constituent colours.
Q9
What is scattering of light?
Scattering is the redirection of light in different
directions by particles present in a medium.
Q10
What is Tyndall effect?
It is the visibility of the path of light due to
scattering by fine or colloidal particles.
Section B – Short Answer Questions
Q11
Explain the role of ciliary muscles in accommodation.
Ciliary muscles change the curvature of the eye lens.
This changes its focal length and allows the eye to
focus clearly on objects at different distances.
Q12
Why can a normal eye not focus clearly on an object
placed extremely close to it?
The eye has a limited ability to increase the
curvature of its lens. Beyond the near point,
sufficient accommodation is not possible for
comfortable clear vision.
Q13
Why is myopia corrected with a concave lens?
A concave lens diverges the incoming light rays
appropriately so that the eye lens can form the
image on the retina instead of in front of it.
Q14
Why is hypermetropia corrected with a convex lens?
A convex lens provides additional convergence to
incoming rays so that the eye can focus the image
on the retina.
Q15
What is presbyopia?
Presbyopia is an age-related defect associated with
reduced accommodation of the eye.
Q16
What happens to white light when it passes through
a prism?
White light can be dispersed into its constituent
colours because different colours undergo different
amounts of deviation.
Q17
Why do stars appear to twinkle?
Starlight passes through changing layers of the
atmosphere, causing atmospheric refraction and
fluctuations in the apparent brightness and position
of the star.
Q18
Why is the sky blue during the day?
Atmospheric particles scatter shorter-wavelength
components of visible light more strongly, making
scattered blue light prominent to an observer.
Section C – Reasoning Questions
Q19
Why does the Sun appear reddish at sunrise and sunset?
At sunrise and sunset, sunlight travels through a
longer atmospheric path. Shorter-wavelength light
is scattered more strongly, so the longer-wavelength
red/orange components become relatively more prominent.
Q20
Why does the Sun appear slightly before actual sunrise?
Due to atmospheric refraction, sunlight bends through
the atmosphere and the Sun can appear above the
geometric horizon before it has actually reached it.
Q21
Why is sunset seen a little later than the actual
geometric sunset?
Atmospheric refraction bends light from the Sun
towards the observer, allowing the Sun to remain
apparently visible for a short additional time.
Q22
Why are stars more suitable than planets for observing
twinkling?
Stars are extremely distant and appear nearly as
point sources. Small atmospheric variations therefore
produce noticeable changes in their apparent brightness.
Q23
Why does the path of a light beam become visible in a
dusty room?
Dust particles scatter some of the light into the
observer's eyes, making the beam path visible.
Q24
Why is the phenomenon seen in a colloidal solution
called the Tyndall effect?
Fine colloidal particles scatter light and make the
path of the beam visible. This characteristic
scattering phenomenon is called the Tyndall effect.
Section D – Diagram-Based Questions
Q25
Draw and label the structure of the human eye.
What to label:
Cornea, iris, pupil, eye lens, ciliary muscles,
retina, optic nerve and other major parts.
Q26
Draw a ray diagram showing correction of myopia.
Diagram should show:
Myopic eye, parallel rays, concave corrective lens
and final focusing on the retina.
Q27
Draw a ray diagram showing correction of hypermetropia.
Diagram should show:
Hypermetropic eye, convex corrective lens and the
corrected image formed on the retina.
Q28
Draw a labelled diagram showing dispersion of white
light through a prism.
Include:
Incident white light, prism, emergent coloured
spectrum and appropriate labels.
Q29
Draw a diagram explaining atmospheric refraction
of light from a star.
Important:
Show the curved path of light through atmospheric
layers and the apparent position of the star.
Q30
Draw a diagram showing the formation of a rainbow.
Include:
Sunlight, water droplet, refraction,
dispersion, internal reflection and emergent
coloured rays.
Section E – Long Answer Questions
Q31
Explain the structure and working of the human eye.
Answer outline:
Describe cornea, iris, pupil, lens, ciliary muscles,
retina and optic nerve. Explain how light enters,
gets focused and produces an image on the retina,
followed by transmission of visual information
to the brain.
Q32
Explain myopia, its causes and its correction.
Answer should include:
Definition, image formation in front of retina,
major causes, suitable concave lens and labelled
correction diagram.
Q33
Explain hypermetropia, its causes and its correction.
Answer should include:
Definition, image formation tendency behind retina,
major causes, suitable convex lens and labelled
correction diagram.
Q34
Explain dispersion of white light by a prism.
Answer should include:
Definition of dispersion, prism setup, spectrum,
different deviations of colours and VIBGYOR.
Q35
Explain atmospheric refraction with suitable examples.
Include:
Changing optical conditions of atmospheric layers,
continuous refraction, twinkling of stars,
advanced sunrise and delayed sunset.
Q36
Explain scattering of light and its important
applications in daily life.
Include:
Meaning of scattering, wavelength dependence,
blue sky, reddish appearance of Sun near sunrise
and sunset and Tyndall effect.
Section F – Competency / Application Based Questions
Q37
A student can read a book clearly but cannot see the
writing on a distant board. Identify the defect,
explain where the image tends to form and name the
corrective lens.
Answer:
The condition is myopia. For a distant object,
the image tends to form in front of the retina.
A suitable concave lens is used for correction.
Q38
A person can see distant objects clearly but has
difficulty reading a nearby book. Identify the
likely defect and its correction.
Answer:
The condition is hypermetropia. A suitable
convex lens is used to provide additional convergence.
Q39
During a classroom experiment, a torch beam becomes
visible when a small amount of milk is added to water.
Explain why.
Answer:
Fine particles in the mixture scatter light and
make the path of the beam visible. This illustrates
the Tyndall effect.
Q40
Two students observe a star and a planet on a clear
night. The star appears to flicker more noticeably.
Explain the observation.
Answer:
Stars are very distant and appear nearly as point
sources. Atmospheric refraction causes noticeable
fluctuations in their apparent brightness.
Q41
Why can a person standing on Earth sometimes see
the Sun even when it is geometrically below the
horizon?
Answer:
Atmospheric refraction bends the Sun's light,
making the Sun appear slightly higher than its
actual geometric position.
Q42
During sunset the Sun appears orange-red. What
happens to the shorter-wavelength components of
sunlight?
Answer:
Due to the longer atmospheric path, shorter-wavelength
light undergoes stronger scattering, so the longer
wavelength red/orange components become relatively
more prominent.
Section G – Assertion / Reason Style
Q43
Assertion: Myopia is corrected using a concave lens.
Reason: A concave lens diverges incident light rays.
Answer:
Both statements are correct, and the reason
correctly explains the role of the concave lens
in myopia correction.
Q44
Assertion: The sky appears blue.
Reason: Shorter wavelengths of visible light are
scattered more strongly by atmospheric particles.
Answer:
Both statements are correct, and the reason
provides the relevant explanation.
Q45
Assertion: Stars appear to twinkle.
Reason: Starlight undergoes atmospheric refraction
through changing atmospheric layers.
Answer:
Both statements are correct, and the reason
correctly describes the phenomenon.
Q46
Assertion: A prism can produce a spectrum from
white light.
Reason: Different colours undergo different
amounts of deviation.
Answer:
Both statements are correct, and the reason
explains dispersion.
⚡ Final Exam Revision
-
Human eye structure and labelled diagram.
-
Power of accommodation.
-
Near point and far point.
-
Myopia, causes, image formation and correction.
-
Hypermetropia, causes, image formation and correction.
-
Presbyopia.
-
Refraction through a prism and angle of deviation.
-
Dispersion and VIBGYOR.
-
Formation of rainbow.
-
Atmospheric refraction.
-
Twinkling of stars.
-
Advanced sunrise and delayed sunset.
-
Scattering of light.
-
Blue colour of sky.
-
Reddish Sun at sunrise and sunset.
-
Tyndall effect.